Identification of loci determining susceptibility to the lethal effects of amyloid precursor protein transgene overexpression

Phenotypes produced by expression of human amyloid precursor protein (APP) transgenes vary depending on the genetic background of the mouse. FVB/N mice overexpressing human APP695 develop a central nervous system disorder and die prematurely, precluding development of Abeta peptide amyloid plaques. 129S6 mice are resistant to the lethal effects of APP overexpression, allowing sufficient levels of Abeta expression for the development of amyloid plaques and age-dependent memory deficits. To identify the genes that determine susceptibility or resistance to APP we analyzed crosses involving FVB/NCr and 129S6.Tg2576 mice that overexpress 'Swedish' mutant (K670N, M671L) APP695. APP transgene-positive FVB129S6F1 (F1) mice are resistant to the lethal effects of APP overexpression, so FVBxF1 backcross and F2 intercross offspring were produced. Analysis of age of death as a quantitative trait revealed significant linkage to loci on proximal chromosome 14 and on chromosome 9; 129S6 alleles protect against the lethal effects of APP. Within the chromosome 14 interval are segments homologous to regions on human chromosome 10 that have been linked to late onset Alzheimer's disease or to levels of Abeta peptide in plasma. However, analysis of plasma Abeta peptide concentrations at 6 weeks in backcross offspring produced no significant linkage. Similarly, elevation of human Abeta peptide concentrations by expression of mutant presenilin transgenes did not increase the proportion of mice dying prematurely, suggesting that early death reflects effects of APP or fragments other than Abeta.     

Comparison of high-energy photon and electron dosimetry for various dosimetry protocols

The American Association of Physicists in Medicine Task Group 51 (TG-51) and the International Atomic Energy Agency (IAEA) published a new high-energy photon and electron dosimetry protocol, in 1999 and 2000, respectively. These protocols are based on the use of an ion chamber having an absorbed-dose to water calibration factor with a 60Co beam. These are different from the predecessors, the TG-21 and IAEA TRS-277 protocols, which require a 60Co exposure or air-kerma calibration factor. The purpose of this work is to present the dose comparison between various dosimetry protocols and the AAPM TG-51 protocol for clinical reference dosimetry of high-energy photon and electron beams. The absorbed-dose to water calculated according to the Japanese Association of Radiological Physics (JARP), International Atomic Energy Agency Technical Report Series No. 277 (IAEA TRS-277) and No. 398 (IAEA TRS-398) protocols is compared to that calculated using the TG-51 protocol. For various Farmer-type chambers in photon beams, TG-51 is found to predict 0.6-2.1% higher dose than JARP. Similarly, TG-51 is found to be higher by 0.7-1.7% than TRS-277. For electron beams TG-51 is higher than JARP by 1.5-3.8% and TRS-277 by 0.2-1.9%. The reasons for these differences are presented in terms of the cavity-gas calibration factor, Ngas, and a dose conversion factor, Fw, which converts the absorbed-dose to air in the chamber to the absorbed-dose to water. The ratio of cavity-gas calibration factors based on absorbed-dose to water calibration factors, N60Co(D,w), in TG-51 and cavity-gas calibration factors which are equivalent to absorbed-dose to air chamber factors, N(D,air), based on the IAEA TRS-381 protocol is 1.008 on average. However, the estimated uncertainty of the ratio between the two cavity-gas calibration factors is 0.9% (1 s.d.) and consequently, the observed difference of 0.8% is not significant. The absorbed-dose to water and exposure or air-kerma calibration factors are based on standards traceable to the National Institute of Standards and Technology (NIST). In contrast, the absorbed-dose to water determined with TRS-398 is in good agreement with TG-51 within about 0.5% for photon and electron beams.     

Comparison of colorimetric,fluorometric, and visual methods for determining anti-influenza (H1N1 and H3N2) virus activities and toxicities of compounds

Methods have been developed previously for rapid evaluation of compounds for antiviral activity in 96-well microplates, which include visual quantitation of antiviral activity based upon inhibition of virus-induced cytopathic effect (CPE) or by less subjective colorimetric or fluorometric means. In the present studies we compared a number of colorimetric (crystal violet, MTT [3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide], and neutral red) and fluorometric (Alamar Blue, bisbenzimide [Hoechst 33258], fluorescein diacetate, and rhodamine 6G) methods to visual scoring of antiviral activity in influenza A virus infections in Madin Darby canine kidney (MDCK) cells. Toxicity determinations using these same methods were also made for anti-influenza inhibitors and other compounds known to inhibit cell proliferation. Against influenza A/Texas/36/91 (H1N1) and A/Sydney/05/97 (H3N2) viruses, visual scoring and dye or stain methods produced results that were not significantly different from each other in deriving 50% virus-inhibitory concentrations (EC(50) values) for six anti-influenza compounds (amantadine, rimantadine, ribavirin, RWJ-270201 [BCX-1812], oseltamivir carboxylate, and zanamivir), with the exception of Alamar Blue which quantified lower EC(50) values than expected. In uninfected replicating cells, the visual and Alamar Blue methods underestimated the 50% cytotoxic concentrations (IC(50) values) of ribavirin, 1-beta-D-arabinofuranosylcytosine, and 6-azauridine, but more accurately assessed the toxicities of amantadine, rimantadine, and cycloheximide. Visual scoring, coupled with the use of one of these dyes or stains except Alamar Blue, can be used to accurately and rapidly quantify the anti-influenza virus activities and toxicities of potential new influenza virus inhibitors. These methods should also be applicable to evaluating antiviral effects against other lytic virus infections.     

Virtual patient simulator for distributed collaborative medical education

Project TOUCH (Telehealth Outreach for Unified Community Health; http://hsc.unm.edu/touch) investigates the feasibility of using advanced technologies to enhance education in an innovative problem-based learning format currently being used in medical school curricula, applying specific clinical case models, and deploying to remote sites/workstations. The University of New Mexico's School of Medicine and the John A. Burns School of Medicine at the University of Hawai'i face similar health care challenges in providing and delivering services and training to remote and rural areas. Recognizing that health care needs are local and require local solutions, both states are committed to improving health care delivery to their unique populations by sharing information and experiences through emerging telehealth technologies by using high-performance computing and communications resources. The purpose of this study is to describe the deployment of a problem-based learning case distributed over the National Computational Science Alliance's Access Grid. Emphasis is placed on the underlying technical components of the TOUCH project, including the virtual reality development tool Flatland, the artificial intelligence-based simulation engine, the Access Grid, high-performance computing platforms, and the software that connects them all. In addition, educational and technical challenges for Project TOUCH are identified.     

Ambient air and its potential effects on conception in vitro

Incidences of chemical air contamination (CAC) are common in assisted reproductive technology, but not reported in peer review format. Justified fear of car and industrial emissions clearly exists among reproductive specialists, but standards for air contents and gaseous emission limits have not been reported. Here, we describe air sampling methods and assay systems which can be applied to any laboratory or laboratory item. It was found that unfiltered outside air may be cleaner than high efficiency particulate air filtration (HEPA) filtered laboratory air or air obtained from incubators, due to accumulation of volatile organic compounds derived from adjacent spaces or specific laboratory products such as compressed CO2, sterile Petri dishes and other materials or devices known to release gaseous emissions. Specific groups of products such as anaesthetic gases, refrigerants, cleaning agents, hydrocarbons and aromatic compounds such as benzene and toluene are described. The latter were shown to accumulate specifically in incubators. Isopropyl alcohol was the most dominant product found, though it was not used by the laboratory staff. Concentrations of this agent were low in incubator air, indicating that it was probably absorbed by the water in the pan or by culture medium. Measures to counter CAC are proposed, including the use of activated carbon filters and oxidizing material placed in the central air handling systems, in separate free-standing units or even inside the incubators.      

Differential effects of the streptococcal fibronectin-binding protein, FBP54, on adhesion of group A streptococci to human buccal cells and HEp-2 tissue culture cells.

We have previously demonstrated that fibronectin mediates streptococcal adhesion to host cells and that streptococci interact primarily with the N-terminal domain of fibronectin. FBP54 is a 54-kDa protein from group A streptococci that binds fibronectin. In this report, we show that the N-terminal domain of fibronectin reacts with FBP54 and preferentially blocks streptococcal adhesion to buccal epithelial cells. FBP54 blocked adhesion to human buccal epithelial cells by 80% in a dose-related fashion. In contrast, FBP54 had little effect on adhesion of group A streptococci to HEp-2 tissue culture cells. The fibronectin-binding domain of FBP54 has been localized to the first 89 N-terminal residues of the protein. Experiments using affinity-purified antibodies to this region indicated that the N terminus of FBP54 is exposed on the surface of streptococci in a manner that can interact with immobilized receptors. Analysis of sera from patients with post-streptococcal glomerulonephritis and acute rheumatic fever indicated that FBP54 is expressed in vivo and is immunogenic in the human host. These data indicate that FBP54 is a streptococcal adhesin that is expressed in the human host and that preferentially mediates adhesion to certain types of human cells.     

Decreased neuroplasticity in minor burn injury survivors compared to non-injured adults: A pilot study in burn injury survivors aged 45 years and older

ObjectiveNeuroplasticity is the capacity of the brain to change or adapt with experience: brain changes occur with use, disuse, and injury. Repetitive transcranial magnetic stimulation (rTMS) can be used to induce neuroplasticity in the human brain. Here, we examined rTMS-induced neuroplasticity in the primary motor cortex in burns survivors and controls without injury, and whether neuroplasticity is associated with functional recovery in burns survivors.MethodsSixteen burn injury survivors (total body surface area of burn injury <15%) and 13 non-injured control participants were tested. Repetitive TMS (specifically, spaced continuous theta-burst stimulation[cTBS]) was applied to induce neuroplasticity 6 and 12 weeks after injury in burn survivors and in two sessions separated by 6 weeks in controls. Motor evoked potentials (MEPs) elicited by single-pulse TMS were measured before and after rTMS to measure neuroplasticity. Burns survivors completed a functional assessment 12 weeks after injury.ResultsNon-injured controls showed decreased MEP amplitude 15?30 min after spaced cTBS in both experimental sessions. Burn survivors showed a smaller change in MEP amplitude after spaced cTBS compared to controls 6 weeks after burn injury but no difference compared to controls 12 weeks after burn injury. In burn survivors, there was a significant positive association between general health outcome (Short-Form Health Survey) and the change in MEP amplitude after spaced cTBS 12 weeks after injury (r=.73, p = .01).ConclusionsThe current findings suggest that burn survivors have a reduced capacity for neuroplasticity early in the recovery period (6 weeks after injury), which normalizes later in the recovery period (12 weeks after injury). Furthermore, the results provide preliminary evidence to suggest that burn survivors with normalized neuroplasticity 12 weeks after injury recover faster after burn injury.     

Improving community health and social care practitioners’ confidence,perceived competence and intention to use behaviour change techniques in health behaviour change conversations

Community health and social care practitioners play an increasingly important role in the health promotion agenda, but lack confidence in having effective health behaviour change (HBC) conversations with members of the public. This study reports the development and evaluation of a training intervention based on health psychology to improve health and social care practitioner self-rated confidence, competence and intention to use five behaviour change techniques (BCTs) in their HBC conversations. A 2-day behavioural science interprofessional skills training course plus online learning module was designed for health and social care staff across North East Scotland, teaching five evidence-based BCTs (e.g. Action Planning), plus person-centred communication skills. Participants rated confidence, competence and future intention to use the BCTs on likert scales (1–10) pre-course and post-course, and provided acceptability data. 177 participants aged 20–64 took part, qualitative and quantitative data suggested that the course had high acceptability. Paired samples t tests (n = 120 with complete data) showed significant improvements in confidence, competence and intention following the course, which remained significant with a conservative analysis (n = 174) assuming no change for missing data. Perceived competence in Action Planning increased most during the course (mean change 3.09). In conclusion, health psychology-based skills training can improve practitioner confidence, competence and intention to use evidence-based BCTs; further evaluation is needed to assess practice change.