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Biomedical subjects

J Kelly

Publications and source records attributed to J Kelly.

At least 37 records · Page 2Linked to original sources

Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004.

In November 2001, the 1st International Symposium on Concussion in Sport was held in Vienna, Austria to provide recommendations for the improvement of safety and health of athletes who suffer concussive injuries in ice hockey, football (soccer), and other sports. The 2nd International Symposium on Concussion in Sport was organised by the same group and held in Prague, Czech Republic in November 2004. It resulted in a revision and update of the Vienna consensus recommendations, which are presented here.

Athletic Injuries↗

Identification of selenomethionine in selenized yeast using two-dimensional liquid chromatography-mass spectrometry based proteomic analysis.

Selenium-enriched yeast has been commonly used as a nutritional supplement. Here we describe a protocol used to investigate the metabolic fate of inorganic selenium in yeast. We provide definitive, mass spectrometry based evidence for the non-specific incorporation of selenomethionine in the yeast proteome involving the replacement of about 30% of all methionine with selenomethionine.

Dietary Supplements↗

Venous thromboembolism after acute ischemic stroke: a prospective study using magnetic resonance direct thrombus imaging.

BACKGROUND AND PURPOSE: We prospectively evaluated the prevalence and clinical risk factors for venous thromboembolism (VTE) after acute ischemic stroke using magnetic resonance direct thrombus imaging, a highly accurate noninvasive technique that directly visualizes thrombus.Method-102 unselected patients with AIS receiving standard prophylaxis with aspirin and graded compression stockings (GCS) were sequentially recruited, underwent regular clinical assessments, and were screened for VTE. RESULTS: The prevalence of all VTE, proximal deep vein thrombosis (PDVT), and pulmonary embolism (PE) after 21 days were 40%, 18%, and 12%, increasing to 63%, 30%, and 20% in patients with Barthel indices (BI) of < or =9 2 days after stroke (BI-2< or =9). Clinical deep vein thrombosis and PE occurred in 3% and 5% overall; half these events were overlooked by the attending team. The true incidence of clinical events is probably higher because the natural history of subclinical PDVT was modified by screening and anticoagulation. BI-2< or =9 or nonambulatory status 2 days after stroke were the clinical factors most strongly associated with subsequent VTE on univariate analysis. Odds ratios for any VTE and PDVT for BI-2< or =9 versus >9 were 8.3 (95% CI, 2.7 to 25.2) and 8.1 (95% CI, 1.7 to 38.3) on multivariable analysis. CONCLUSIONS: BI < or =9 or nonambulatory status around the time of admission identifies a subgroup of acute ischemic stroke patients at very high risk for VTE in whom the current strategy of thromboprophylaxis may be inadequate. Future thromboprophylactic studies should focus on the patients at high risk defined in this study.

Aged↗

A study of bone mineral density in women with forearm fracture in Northern Ireland.

A group of Northern Ireland women aged 40-75 years of age with low-trauma forearm fracture were studied to determine the incidence of such fractures and the prevalence of osteoporosis in this fracture population. A total of 1,147 subjects were identified in 1997 and 1998 throughout Northern Ireland following low-trauma forearm fractures, as well as 699 residents in the Eastern Health and Social Services Board (EHSSB), enabling calculation of the annual incidence rate of new low-trauma forearm fractures at 2.69/1,000 population aged 40-75. A total of 375 participants consented to have bone mineral density (BMD) measurements undertaken at the femoral neck, spine, and forearm using a Lunar Expert bone densitometer. Osteoporosis at the femur was present in 14% of women, at the spine in 29%, and at the forearm in 32%. A total of 45% were osteoporotic at one or more measured sites, but only 18% were on treatment for osteoporosis. Additional significant risk factors identified included an early menopause in 24.5% and current or previous corticosteroid use in 13%. Only 1.6% received information on treatment of osteoporosis at the time of fracture. Increased awareness is needed in both primary and secondary care including fracture services to improve treatment of women with low-trauma fracture.

Adult↗

Measurement of the electric form factor of the neutron at Q2=0.5 and 1.0 GeV2/c2.

The electric form factor of the neutron was determined from measurements of the d-->(e-->,e'n)p reaction for quasielastic kinematics. Polarized electrons were scattered off a polarized deuterated ammonia (15ND3) target in which the deuteron polarization was perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle detector. We find G(n)(E)=0.0526+/-0.0033(stat)+/-0.0026(sys) and 0.0454+/-0.0054+/-0.0037 at Q(2)=0.5 and 1.0 (GeV/c)(2), respectively.

Journal Article↗

Three-dimensional orientational order in the bulk and on the surface of polymer films and its effect on liquid-crystal alignment.

The correlation between orientation ordering of polymer chains in the bulk of polymer film and at the polymer-liquid-crystal (LC) interface has been studied to determine it's role in LC alignment. The bulk and surface ordering of polymer were investigated by null ellipsometry and x-ray reflectivity, respectively. Two kinds of liquid-crystalline polymers were used; side-chain azopolymers with azochromophores containing hydrophobic OC4H9 alkyl chain (P1) and strongly polar NO2 group (P2) as the end substituents. The uniaxial tilt orientation of azochromophores in the films of both polymers was induced by the oblique irradiation with unpolarized UV light. The two polymers exhibit similar chain orientation but different ordering of azochromophores on the surface of the films of P1 and P2. Surface ordering of P1 films correlates very well with the order in the bulk of the film, which are essentially determined by the UV exposure. However, orientational order of polymer chains at the surface of P2 films is different from that in its bulk and is not determined by UV exposure. This is explained by strong aggregation of azochromophores during its self-assembling at the polymer-air interface. The LC alignment is determined by the surface ordering of azochromophores. The results imply that ordering tendency can be effectively transferred from polymer bulk to polymer surface and then to LC if it is not lost at the polymer-LC interface.

Journal Article↗

Precision measurement of the neutron spin asymmetryA(n)(1) and spin-flavor decomposition in the valence quark region.

We have measured the neutron spin asymmetry A(n)(1) with high precision at three kinematics in the deep inelastic region at x=0.33, 0.47, and 0.60, and Q(2)=2.7, 3.5, and 4.8 (GeV/c)(2), respectively. Our results unambiguously show, for the first time, that A(n)(1) crosses zero around x=0.47 and becomes significantly positive at x=0.60. Combined with the world proton data, polarized quark distributions were extracted. Our results, in general, agree with relativistic constituent quark models and with perturbative quantum chromodynamics (PQCD) analyses based on the earlier data. However they deviate from PQCD predictions based on hadron helicity conservation.

Journal Article↗

Intricacies and inter-relationships between HIV disclosure and HAART: a qualitative study.

This study aimed to understand whether and how highly active antiretroviral treatment (HAART) affects views and patterns of disclosure and how disclosure interacts with treatment decisions. One hundred and fifty-two HIV-positive adults (52 MSM, 56 women and 44 IDU men) from four US cities participated in two to three-hour, semi-structured interviews in 1998-99. Results indicate that HAART interacts with and shapes HIV disclosure issues in several ways. Medications may 'out' people living with HIV. Thus, in different settings (e.g. work, prisons, drug rehabs and public situations), some try to hide medications or modify dosing schedules, which can contribute to non-adherence, and affect sexual behaviours. Disclosure of HIV and/or HAART may also result in antagonism from others who hold negative attitudes and beliefs about HAART, potentially impeding adherence. Observable side effects of medications can also 'out' individuals. Conversely, medications may improve appearance, delaying or impeding disclosure. Some wait until they are on HAART and look 'well' before disclosing; some who look healthy as a result of medication deny being HIV-positive. Alternatively, HIV disclosure can lead to support that facilitates initiation of, and adherence to, treatment. HIV disclosure and adherence can shape one another in critical ways. Yet these interactions have been under-studied and need to be further examined. Interventions and studies concerning each of these domains have generally been separate, but need to be integrated, and the importance of relationships between these two areas needs to be recognized.

Adult↗

Dehydration and venous thromboembolism after acute stroke.

BACKGROUND: Although it is widely assumed that dehydration predisposes to venous thromboembolism (VTE), there are no clinical studies to support this. AIM: To evaluate the relationship between biochemical indices of dehydration and VTE after acute ischaemic stroke (AIS). DESIGN: Prospective observational study. METHODS: Unselected AIS patients (n = 102) receiving standard thromboprophylaxis with aspirin and graded compression stockings, underwent serial measurements of serum urea, creatinine and osmolality, and were screened for VTE using magnetic resonance direct thrombus imaging. RESULTS: Serum osmolality of >297 mOsm/kg, urea >7.5 mmol/l and urea:creatinine ratio (mmol:mmol) >80 a few days post-AIS were associated with odds ratios for VTE of, respectively, 4.7, 2.8 and 3.4 (p = 0.02, 0.05, 0.02) on multivariable analysis. DISCUSSION: Dehydration after AIS is strongly independently associated with VTE, reinforcing the importance of maintaining adequate hydration in these patients.

Aged↗

Hepatic interleuklin 15 (IL-15) expression: implications for local NK/NKT cell homeostasis and development.

Interleukin 15 (IL-15) is critical for the development of human and murine natural killer (NK) cells and hepatic-derived NK T cells (NKT) in mice, and for the homeostatic maintenance of NK/NKT and CD8(+) memory T cells. The lymphocyte repertoire of an adult human liver includes significant populations of NK and NKT-like cells, which may arise locally from hepatic haematopoietic stem cells (HSCs). We investigated hepatic IL-15 levels and the expression of IL-2/IL-15-receptor beta-chain (IL-2/IL-15Rbeta; CD122) on mature hepatic lymphocytes and HSCs. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect secreted/intracellular IL-15 transcripts. IL-15 protein was localized using immunohistochemistry; levels were measured by enzyme-linked immunosorbent assay IL-2/IL-15Rbeta expression by flow-cytometry. Normal hepatic IL-15 protein was detected at 0.43 ng/100 mg total protein (n = 11, range 0.10 ng-0.9 ng). There was a significant increase in HCV-infected tissue (1.78 ng, P < 0.005, n = 11, range 0.18-2.43 ng). The staining pattern suggests that infiltrating monocytes and tissue resident Kupffer cells are the main producers. IL-15 protein was detected in supernatants from cultured liver biopsy specimens in the absence of stimulation (mean 175.8 pg/100 mg wet tissue, n = 3), which increased significantly upon stimulation (P < 0.05, mean 231.21 pg). On average, 61% of hepatic HSCs expressed IL-2/IL-15Rbeta suggesting a local lymphopoietic role. Eighty per cent of NK and 45.8% of CD56(+) T cells expressed IL-2/IL-15Rbeta, suggesting involvement in local CD56(+) cell activation and expansion. Constitutive expression of IL-15 protein and IL-2/IL-15Rbeta on hepatic lymphocytes suggests a key role in the generation and maintenance of the unique hepatic lymphoid repertoire. The significant increase observed in HCV-infected liver suggests a role for IL-15 in host antiviral responses in the liver.

Adolescent↗

Electrical and neurotransmitter activity of mature neurons derived from mouse embryonic stem cells by Sox-1 lineage selection and directed differentiation.

Sx1TV2/16C is a mouse embryonic stem (ES) cell line in which one copy of the Sox1 gene, an early neuroectodermal marker, has been targeted with a neomycin (G418) selection cassette. A combination of directed differentiation with retinoic acid and G418 selection results in an enriched neural stem cell population that can be further differentiated into neurons. After 6-7 days post-plating (D6-7PP) most neurons readily fired tetrodotoxin (TTX)-sensitive action potentials due to the expression of TTX-sensitive Na(+) and tetraethylammonium (TEA)-sensitive K(+) channels. Neurons reached their maximal cell capacitance after D6-7PP; however, ion channel expression continued until at least D21PP. The percentage of cells receiving spontaneous synaptic currents (s.s.c.) increased with days in culture until 100% of cells received a synaptic input by D20PP. Spontaneous synaptic currents were reduced in amplitude and frequency by TTX, or upon exposure to a Ca(2+)-free, 2.5 mm Mg(2+) saline. S.s.c. of rapid decay time constants were preferentially blocked by the nonNMDA glutamatergic receptor antagonists CNQX or NBQX. Ca(2+) levels within ES cell-derived neurons increased in response to glutamate receptor agonists l-glutamate, AMPA, N-methyl-d-aspartate (NMDA) and kainic acid and to acetylcholine, ATP and dopamine. ES cell-derived neurons also generated cationic and Cl(-)-selective currents in response to NMDA and glycine or GABA, respectively. It was concluded that ES-derived neurons fire action potentials, receive excitatory and inhibitory synaptic input and respond to various neurotransmitters in a manner akin to primary central neurons.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

Screening for proximal deep vein thrombosis after acute ischemic stroke: a prospective study using clinical factors and plasma D-dimers.

Deep vein thrombosis (DVT) remains common in patients with acute ischemic stroke (AIS) receiving aspirin and graded compression stockings (considered standard thromboprophylaxis in the UK), most events occurring in patients with Barthel indices (BI) of <9 ('severe stroke') around the time of admission. In the absence of data indicating improved clinical outcomes with use of low-dose anticoagulant thromboprophylaxis, we evaluated the hypothesis that plasma D-dimers (D-d) might be a valuable initial screening test for proximal DVT (PDVT), facilitating selective use of imaging. One hundred and two unselected AIS-patients receiving aspirin/graded compression stockings thromboprophylaxis were screened for DVT using magnetic resonance direct thrombus imaging, a highly accurate non-invasive technique which directly visualizes thrombus. D-d (VIDAS and IL test D-d assays) were measured on recruitment and at weekly intervals. Median D-d were significantly higher throughout the study in patients with severe stroke who developed PDVT vs. those with severe stroke not developing PDVT, differences being most marked around day 9. Depending on the discriminatory threshold used, a single D-d measurement at this time in patients with severe-AIS allowed identification of a subgroup with ~50% prevalence of PDVT. Sensitivity of these strategies for PDVT was 67-83%, at a cost of imaging 22-30% of the entire cohort of patients. A single measurement of BI around the time of admission and D-d level at day 9 in AIS-patients receiving aspirin/graded compression stockings thromboprophylaxis allows identification of a subgroup containing a substantial proportion of all PDVTs who could be selectively imaged.

Age Factors↗

Are referrals to occupational therapy for developmental coordination disorder appropriate?

AIMS: To assess children referred to the Occupational Therapy Service in Gwent with a presumptive diagnosis of developmental coordination disorder (DCD) in order to investigate the appropriateness of their referral. METHODS: Non-urgent referrals to the occupational therapy team for children with coordination difficulties in Gwent between June 2001 and February 2002 were studied. RESULTS: Eighty nine children, aged 5-10 years, were identified. Thirteen children who would not meet the DCD criteria were excluded. This left 76 children, 67 of whom were actually assessed. If the 15th centile for the Movement ABC is used, 26 children met and 41 failed one of the four criteria in DSM IV (38%). If the 5th centile is used, 21 children met and 46 failed one of the four criteria in the DSM (31%). Of the major groups of referrers, school nurses did the best with 48% success rate; better than the paediatricians with 32%. The worst success rate was in educational psychologists and teachers, with only 20% of cases referred actually having DCD. These differences did not quite reach statistical significance. CONCLUSIONS: Less than a third of referrals to occupational therapy for DCD actually have the diagnosis. This suggests that referrers need further training and guidance. This includes a knowledge and understanding of the DSM IV criteria and their interpretation. This would reduce the number of time consuming, unnecessary assessments being done. A triage procedure with a checklist would be a good way forward and we hope to devise one to assist referrers with this process.

Activities of Daily Living↗

The diagnosis of borderline iron deficiency: results of a therapeutic trial.

BACKGROUND: Iron deficiency is common in early childhood and has been associated with developmental delay. It is not known how reliably markers of iron deficiency identify true iron deficiency, defined as a therapeutic response to oral iron. METHODS: The subjects were members of the Millennium Baby Study cohort. At age 13 months a venous blood sample was taken for mean cell volume (MCV), haemoglobin, mean cell haemoglobin (MCH), ferritin, and zinc protoporphyrin (ZPP). Children with abnormal values were offered treatment with oral iron and dietary modification, and re-sampled after 3 months. RESULTS: Samples were obtained for 462 children. All markers were moderately correlated with each other except ferritin. Treatment was offered to 147 (32%) children with at least one abnormal value, of whom 126 (86%) were re-sampled. Children with a haemoglobin or an MCH below the screening cut off, or with abnormal values for two or more of the remaining three measures, showed a large therapeutic response to iron, but isolated abnormalities of MCV, ZPP, or ferritin were not consistently associated with a response. Of the screened population 13% could be defined as iron deficient (abnormal haemoglobin or MCH, or abnormal levels of two or more of the remaining three markers), but this was not strongly associated with any dietary, demographic, or anthropometric characteristic. CONCLUSIONS: Low total or mean cell haemoglobin in isolation is a specific marker of iron deficiency, but other markers are only predictive when found in combination with other abnormal values.

Anemia, Iron-Deficiency↗

Anticoagulation or inferior vena cava filter placement for patients with primary intracerebral hemorrhage developing venous thromboembolism?

BACKGROUND: Most patients with primary intracerebral hemorrhage developing clinically apparent proximal deep vein thrombosis (DVT) and/or pulmonary embolism (PE) require treatment with either anticoagulants or inferior vena cava filter insertion. Although the latter probably reduces the immediate risk of incident or recurrent PE and surmounts the undefined risk of recurrent intracranial bleeding with anticoagulation, the issue of preventing further thrombus propagation is not addressed, and there are associated short- and long-term risks, including a greater incidence of recurrent DVT. SUMMARY OF REVIEW: There are no data from randomized trials to clarify optimum treatment in these patients; indeed, the feasibility of such studies is questionable. Hence, treatment decisions continue to be made on an individualized basis and should include assimilation of information on key factors such as time elapsed post-stroke and lobar versus deep hemispheric location of the index event, natural history studies demonstrating a two-fold risk of recurrent intracerebral hemorrhage in the former subgroup. CONCLUSIONS: In patients selected for anticoagulation, data from nonstroke patients suggest that a 5- to 10-day course of full-dose low-molecular-weight heparin followed by 3 months of lower-dose low-molecular-weight heparin is at least as effective as warfarin and may be associated with fewer hemorrhagic complications.

Anticoagulants↗

Photoinduced three-dimensional orientational order in side chain liquid crystalline azopolymers.

We apply experimental technique based on the combination of methods dealing with principal refractive indices and absorption coefficients to study the photoinduced three-dimensional (3D) orientational order in the films of liquid crystalline (LC) azopolymers. The technique is used to identify 3D orientational configurations of trans azobenzene chromophores and to characterize the degree of ordering in terms of order parameters. We study two types of LC azopolymers which form structures with preferred in-plane and out-of-plane alignment of azochromophores, respectively. Using irradiation with the polarized light of two different wavelengths, we find that the kinetics of photoinduced anisotropy can be dominated by either photoreorientation (angular redistribution of trans chromophores) or photoselection (angular selective trans-cis isomerization) mechanisms depending on the wavelength. At the early stages of irradiation, the films of both azopolymers are biaxial. This biaxiality disappears on reaching a state of photosaturation. In the regime of photoselection, the photosaturated state of the film is optically isotropic. But, in the case of the photoreorientation mechanism, anisotropy of this state is uniaxial with the optical axis dependent on the preferential alignment of azochromophores. We formulate the phenomenological model describing the kinetics of photoinduced anisotropy in terms of the isomer concentrations and the order parameter tensor. We present the numerical results for absorption coefficients that are found to be in good agreement with the experimental data. The model is also used to interpret the effect of changing the mechanism with the wavelength of the pumping light.

Absorption↗