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Biomedical subjects

A Smith

Publications and source records attributed to A Smith.

At least 109 records · Page 6Linked to original sources

Do real time 'flu spotter rates warn us about impending emergency admissions and deaths?

This study aimed to determine how general practice influenza surveillance ('flu spotter) data related to hospital admissions and deaths in Scotland during the winter period. 'Flu spotter rates correlated well with influenza-related emergency admissions and deaths, and deaths from all causes, particularly during 'peak' influenza years. They may be used in a predictive model for influenza-related hospital admissions and deaths.

Disease Outbreaks↗

Buyers beware!

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Dental Instruments↗

Observation of the charge symmetry breaking d+d-->4He+pi(0) reaction near threshold.

We report the first observation of the charge symmetry breaking d+d-->4He+pi(0) reaction near threshold. Measurements using a magnetic channel (gated by two photons) of the 4He scattering angle and momentum (from time of flight) permitted reconstruction of the pi(0) "missing mass," the quantity used to separate 4He+pi(0) events from the continuum of double radiative capture 4He+gamma+gamma events. We measured total cross sections for neutral pion production of 12.7+/-2.2 pb at 228.5 MeV and 15.1+/-3.1 pb at 231.8 MeV. The uncertainty is dominated by statistical errors. These cross sections arise fundamentally from the down-up quark mass difference and quark electromagnetic effects that contribute in part through meson mixing (e.g., pi(0)-eta) mechanisms.

Journal Article↗

Branching fractions of tau leptons to three charged hadrons.

From electron-positron collision data collected with the CLEO detector operating at Cornell Electron Storage Ring near sqrt[s]=10.6 GeV, improved measurements of the branching fractions for tau decays into three explicitly identified hadrons and a neutrino are presented as B(tau(-)-->pi(-)pi(+)pi(-)nu(tau))=(9.13+/-0.05+/-0.46)%, B(tau(-)-->K-pi(+)pi(-)nu(tau))=(3.84+/-0.14+/-0.38) x 10(-3), B(tau(-)-->K-K+pi(-)nu(tau))=(1.55+/-0.06+/-0.09) x 10(-3), and B(tau(-)-->K-K+K-nu(tau))<3.7 x 10(-5) at 90% C.L., where the uncertainties are statistical and systematic, respectively.

Journal Article↗

First search for the flavor changing neutral current decay D0-->gammagamma.

Using 13.8 fb(-1) of data collected at or just below the Upsilon(4S) with the CLEO detector, we report the result of a search for the flavor changing neutral current process D0-->gammagamma. We observe no significant signal for this decay mode and determine 90% confidence level upper limits on the branching fractions B(D0-->gammagamma)/B(D0-->pi(0)pi(0))<0.033 and B(D0-->gammagamma)<2.9 x 10(-5).

Journal Article↗

Failure of thrombus to resolve in urokinase-type plasminogen activator gene-knockout mice: rescue by normal bone marrow-derived cells.

BACKGROUND: Monocytes may have an important role in the resolution of venous thrombosis. Increased expression of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) is associated with an ingress of monocytes into the thrombus. This study was designed to evaluate the importance of these activators in thrombus resolution. METHODS AND RESULTS: Inferior caval vein thrombosis was induced in cohorts of adult wild-type, uPA gene-knockout (uPA-/-), and tPA gene-knockout (tPA-/-) mice in a flow model. Thrombi were harvested from wild-type and uPA-/- mice (n=60 per group) between 1 and 60 days. Thrombi were also obtained from groups of wild-type and tPA-/- mice (n=24 per group) between 1 and 28 days. Thrombus size and macrophage content were measured by computer-assisted image analysis. Thrombus resolution was significantly impaired in the uPA-/- mice compared with wild-type controls (P<0.0001) but was unaffected in tPA-/- mice. Monocyte content in wild-type mice was highest at 14 days after thrombus induction and was approximately 4 times greater than in uPA-/- mice (P=0.0043). Thrombus size in uPA-/- mice transplanted with wild-type marrow (0.29+/-0.06 mm2) was significantly smaller than in uPA-/- mice given uPA-/- bone marrow (3.9+/-1.1 mm2) (P=0.0022). Donor bone marrow-derived cells expressing LacZ were present in the thrombus after transplantation. CONCLUSIONS: The resolution of experimental venous thrombus is dependent on uPA but is unaffected by the absence of tPA. Absence of uPA is also associated with delayed monocyte recruitment into the thrombus. Transplanting wild-type bone marrow restores thrombus resolution in uPA-/- animals, suggesting an important role for bone marrow-derived cells in this process.

Animals↗

Feasibility and compliance of automated measurement of quality of life in oncology practice.

PURPOSE: Systematic quality-of-life (QOL) assessment may have value in oncology practice by increasing awareness of a wide range of issues, possibly increasing detection of psychologic morbidity, social problems, and changes in physical status, and improving care and its outcomes. However, logistic problems are substantial. Automated systems solve many of these problems. We field-tested the feasibility and compliance that can be achieved using a computer touchscreen system in two consecutive studies. PATIENTS AND METHODS: In study 1, a prospective cohort of 272 patients was offered QOL assessment at each clinic appointment for 6 months. In study 2, all patients (N = 1,291) were offered QOL assessment as part of clinic routine during a 12-week period. RESULTS: In study 1, 82% of patients agreed to take part, but over time, compliance was poor (median, 40%; mean, 43%) and deteriorated with longer follow-up. In study 2, the overall compliance was greatly increased (median, 100%; mean, 70%), and compliance was retained over multiple visits. In study 1, compliance was better in younger patients, males, and socially advantaged patients, but was not affected by the presence of depression or anxiety, or QOL. In the second study, building on experience in the first study, data collection and storage in the computer system was excellent, achieving 98% of collected data stored in one center. In general, patients were comfortable with the computers and the approach. Data collection on the wards was more difficult and less complete than in clinics, especially for patients undergoing acute admissions. CONCLUSION: Feasibility with higher compliance was demonstrated in study 2, in which the data collection was integrated into routine care, and can be improved with further technical initiatives and education of staff.

Adult↗

Distribution of polycyclic aromatic hydrocarbons in agricultural soils in South Korea.

The content and type of polycyclic aromatic hydrocarbons (PAH) in soils from paddy fields and upland areas in South Korea were determined using gas chromatography linked to mass spectrometry (GC-MS). The distribution map of total PAH content was obtained as a contour plot using a geographical information system. The overall distribution of PAH was found to be closely related to the pollution sources, the size of city and the type of industry. The average content of total PAH in all samples was 236 microgkg(-1), and the range was from 23.3 to 2834 microgkg(-1). The highest concentrations were found in soils sampled near iron processing plants. The concentration of PAH decreased in the order fluoroanthene>benzo(b)fluoroanthene>pyrene. Special PAH compound ratios, such as phenanthrene/anthracene and fluoroanthene/pyrene, were calculated to evaluate the origin. The collected data suggested that the pyrogenic origins such as motor vehicle exhaust and heavy industry emission were the dominant source of PAH in Korean soils.

Korea↗

Hypodiploidy of 37 chromosomes in an adult patient with acute lymphoblastic leukemia.

We present a 42-year-old man with acute lymphoblastic leukemia and hypodiploidy at diagnosis. Chromosome count was 37, with a mixture of numerical and structural abnormalities. The patient died 9 months post diagnosis, during which time three further cytogenetic tests were performed. The core abnormalities seen upon diagnosis were present at 7 and 9 months after diagnosis, with a duplication of the abnormal hypodiploid karyotype on the last specimen. While considerable imbalances were present as a result of whole chromosome aneuploidy, no region was obviously nullisomic.

Adult↗

Analysis of the Leeds-Keio ligament for extensor mechanism repair: favourable mechanical and functional outcome.

Many techniques have been described for the challenging problem of extensor mechanism rupture, including the use of synthetic grafts. In 1994 Fujikawa et al. [J. Bone Surg. 1994:76B:200-203] reported excellent results using the Leeds-Keio polyester ligament. Patients were mobilised early, had few post operative complications and minimal extensor lag. This is the first independent assessment of this technique using both subjective and objective analysis of outcome. We reviewed 11 patients (12 knees) whose extensor mechanisms were repaired as described in the original paper. At a mean of 3 years after surgery there were no infections and no re-ruptures. Good functional recovery was observed with a mean Tegner activity score of 1.7, Lysholm score of 66 and Irrgang score of 58%. Indeed, 80% of working patients returned to their former employment. However, objective tests showed peak extensor torque recovered to only half normal strength. We conclude the results of this technique of repair compare favourably with other described techniques especially in complex cases.

Adult↗

Mesenchymal stem cells combined with biphasic calcium phosphate ceramics promote bone regeneration.

The reconstruction and repair of large bone defects, resulting from trauma, cancer or metabolic disorders, is a major clinical challenge in orthopaedics. Clinically available biological and synthetic grafts have clear limitations that necessitate the development of new graft materials and/or strategies. Human mesenchymal stem cells (MSCs), obtained from the adult bone marrow, are multipotent cells capable of differentiating into various mesenchymal tissues. Of particular interest is the ability of these cells to differentiate into osteoblasts, or bone-forming cells. At Osiris, we have extensively characterized MSCs and have demonstrated MSCs can induce bone repair when implanted in vivo in combination with a biphasic calcium phosphate, specifically hydroxyapatite/tricalcium phosphate. This article reviews previous and current studies utilizing mesenchymal stem cells and biphasic calcium phosphates in bone repair.

Journal Article↗

Enabling topical immunization via microporation: a novel method for pain-free and needle-free delivery of adenovirus-based vaccines.

The skin represents an excellent site for vaccine inoculation due to its natural role as a first line of contact with foreign pathogens and the high local frequency of antigen presenting cells. To facilitate skin-directed immunization, a new technique has been developed (termed microporation) whereby a vaporization process is used to remove tiny areas of the stratum corneum creating microscopic pores that allow access to the underlying viable epidermis. Reporter gene expression was 100-fold increased following application of an adenovirus vector to microporated skin when compared to intact skin. Furthermore, 10-100-fold greater cellular and humoral immune responses were observed following topical administration of an adenovirus vaccine to microporated skin versus intact skin. Hairless mice responded to the microporated adenovirus vaccine equivalently to mice with normal hair follicle distribution demonstrating the activity of the microporated vaccine was not related to follicle count. In a tumor challenge model using a surrogate antigen, microporation increased vaccine efficacy by approximately 100-fold compared to intact skin. Finally, microporation enabled delivery of an adenovirus vaccine carrying a relevant melanoma antigen resulting in the development of auto-immune vitiligo and tumor protection. Thus, the microporation technology has proven to be a reliable and easy method to enable skin-directed vaccination.

Adenoviridae↗

Stable rAAV-mediated transduction of rod and cone photoreceptors in the canine retina.

Recombinant adeno-associated virus (rAAV) vectors are attractive candidates for the treatment of inherited and acquired retinal disease. Although rAAV vectors are well characterized in rodent models, a prerequisite to their clinical application in human patients is the thorough evaluation of their efficacy and safety in intermediate animal models. In this study, we describe rAAV-2-mediated expression of GFP reporter gene in retinal cells following local vector delivery in dogs. Subretinal delivery of rAAV.CMV.GFP was performed unilaterally in eight normal dogs from 6 weeks of age. The area of retinal transduction was maximized by the optimization of surgical techniques for subretinal vector delivery by pars-plana vitrectomy and the use of fine-gauge subretinal cannulae to create multiple retinotomies. rAAV-2 vectors mediated efficient stable reporter gene expression in photoreceptors and retinal pigment epithelial cells. We found efficient transduction of cone photoreceptors in addition to rods in both the canine retina and after subretinal vector delivery in another intermediate animal model, the feline retina. GFP expression in dogs was confined to the area of the retinal bleb and was sustained in cells at this site for at least 18 months. Electroretinography demonstrated a modest reduction in global rod-mediated retinal function following subretinal delivery of rAAV.CMV.GFP. Three of the eight animals developed delayed-onset intraocular inflammation, in two cases associated with a serum antibody response to GFP protein. We conclude that rAAV-2 vectors mediate efficient sustained transgene expression in rod and cone photoreceptors following subretinal delivery in this intermediate animal model. The possibility of adverse effects including intraocular immune responses and reduced retinal function requires further investigation prior to clinical applications in patients.

Animals↗

Dynamic contrast enhanced magnetic resonance imaging aids the surgical management of invasive lobular breast cancer.

AIMS: Infiltrating Lobular Carcinoma (ILC) accounts for 5-10% of all breast cancers and is associated with subtle clinical and mammographic changes. It is also frequently multifocal and traditional diagnostic methods are unable to reliably detect this preoperatively. The aim of the study was to evaluate the efficacy of current imaging modalities compared with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in the evaluation of ILC. METHODS: Data from women with ILC treated between 1996 and 2000 who had undergone preoperative triple assessment and DCE-MRI was analysed. The diagnostic accuracy and the detection of multifocal disease for each modality was assessed and any changes in clinical management following DCE-MRI were recorded. RESULTS: Twenty-one women (mean age 57, range 43-72 years) were recruited. The sensitivity of X-ray mammography, ultrasound, clinical assessment, fine needle aspiration cytology or core biopsy and DCE-MRI was 90.5, 87.5, 76.2, 85.7 and 95.2% respectively. DCE-MRI identified all the patients with subsequently histologically proven multifocal disease (n=11) with PPV and NPV of 100 and 95.2% respectively. X-ray mammography and ultrasound combined identified only 27% (n=3/11) with PPV and NPV of 100 and 55.6% respectively. Management was changed in 24% (5/21) of the cases following DCE-MRI. CONCLUSION: DCE-MRI has a higher sensitivity than other imaging modalities and is able to accurately delineate multifocal disease not evident on conventional imaging. DCE-MRI should therefore be used for accurate staging prior to surgery for invasive lobular breast cancer.

Adult↗

Expertise in practice: an ethnographic study exploring acquisition and use of knowledge in anaesthesia.

BACKGROUND: Expert professional practice in any field is known to rely on both explicit (formal) and tacit (personal) forms of knowledge. Current anaesthetic training programmes appear to favour explicit knowledge and measurable competencies. We aimed to describe and explore the way different types of knowledge are learned and used in anaesthetic practice. METHOD: Qualitative approach using non-participant observation of, and semi-structured interviews with, anaesthetic staff in two English hospitals. RESULTS: The development of expertise in anaesthesia rests on the ability to reconcile and interpret many sources of knowledge--clinical, social, electronic, and experiential--and formal theoretical learning. Experts have mastered technical skills but are also able to understand the dynamic and uncertain condition of the anaesthetized patient and respond to changes in it. This expertise is acquired by working with colleagues, and, importantly, by working independently, to develop personal routines. Routines mark the successful incorporation of new knowledge but also function as a defence against the inherent uncertainty of anaesthetic practice. The habits seen in experts' routines are preferred ways of working chosen from a larger repertoire of techniques which can also be mobilized as changing circumstances demand. CONCLUSIONS: Opportunities for developing expertise are linked to the independent development of personal routines. Evidence-based approaches to professional practice may obscure the role played by the interpretation of knowledge. We suggest that the restriction of apprenticeship-style training threatens the acquisition of anaesthetic expertise as defined in this paper.

Anesthesia↗

Recommendations for conducting the in vivo alkaline Comet assay. 4th International Comet Assay Workshop.

The in vivo alkaline single cell gel electrophoresis assay, hereafter the Comet assay, can be used to investigate the genotoxicity of industrial chemicals, biocides, agrochemicals and pharmaceuticals. The major advantages of this assay include the relative ease of application to any tissue of interest, the detection of multiple classes of DNA damage and the generation of data at the level of the single cell. These features give the Comet assay potential advantages over other in vivo test methods, which are limited largely to proliferating cells and/or a single tissue. The Comet assay has demonstrated its reliability in many testing circumstances and is, in general, considered to be acceptable for regulatory purposes. However, despite the considerable data published on the in vivo Comet assay and the general agreement within the international scientific community over many protocol-related issues, it was felt that a document giving detailed practical guidance on the protocol required for regulatory acceptance of the assay was required. In a recent meeting held in conjunction with the 4th International Comet Assay Workshop (Ulm, Germany, 22-25 July 2001) an expert panel reviewed existing data and recent developments of the Comet assay with a view to developing such a document. This paper is intended to act as an update to the more general guidelines which were published as a result of the International Workshop on Genotoxicity Test Procedures. The recommendations are also seen as a major step towards gaining more formal regulatory acceptance of the Comet assay.

Animals↗

Screening for Neisseria gonorrhoeae and Chlamydia trachomatis in men who have sex with men at male-only saunas.

BACKGROUND AND OBJECTIVES: In response to increases in sexually transmissible infections (STI) and HIV infection rates among men who have sex with men (MSM), the current study aimed to investigate the feasibility of a screening program at male-only saunas in Melbourne, Australia. GOAL: The goal was to determine (1) the participation rate, and the proportion whom obtain test results; (2) the prevalence of gonorrhea and chlamydia; and (3) to evaluate risk factors for STI acquisition. STUDY DESIGN: We used a cross-sectional design. Pharyngeal, rectal, and urethral specimens were collected from participants, and tested for Chlamydia trachomatis and Neisseria gonorrhoeae by polymerase chain reaction (PCR). RESULTS: There was a participation rate of 24% (n=521), and 70% obtained their test results. The infection rate in those who failed to collect their results was no different than those seeking theirs. The proportion of participants with PCR-detected gonorrhea and/or chlamydia infection was high, 10.7%. The presence of infection was associated with seeking sexual health care in the last year. CONCLUSION: The high prevalence rate of gonorrhea and chlamydia supports the concept of a screening program in Melbourne male-only saunas. The low participation rate has highlighted the need to consider alternative methods for making contact with men in the saunas or offering incentives to participate in future screening programs. Although anonymous participation encouraged participation for some men, future programs should attempt to obtain contact details for follow up of positive test results.

Adult↗