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Biomedical subjects

J Ellison

Publications and source records attributed to J Ellison.

At least 19 recordsLinked to original sources
PubMed2006

Characteristics of adolescent smoking in high school students in California.

PURPOSE: This pilot study assessed smoking-related behaviors, experiences, and beliefs among a sample of continuation high school students in California to inform dental hygienists about adolescent tobacco use and to assist with the development of effective tobacco cessation intervention strategies. METHODS: After gaining informed consent, we conducted a self-administered questionnaire among 117 adolescent volunteers in rural northern California. The questionnaire assessed demographic variables, lifetime tobacco use, current alcohol use and tobacco use status, early smoking experiences and sensations, factors that might motivate a quit attempt, depression index scores, and other psychosocial variables associated with adolescent smoking. Means and frequencies were generated to evaluate characteristics of tobacco use in this sample of adolescents. Variables of interest were stratified by regular and social smokers. Univariate association of smoking with alcohol use is described by an odds ratio with a 95% confidence interval. Wilcoxon rank sum tests were used to evaluate gender differences among mean depression index scores. RESULTS: Fifty percent of subjects were current smokers, 21% had tried smoking, 5% were former smokers, and 24% had never smoked. Current smokers were 8 times more likely to drink alcohol compared to nonsmokers (OR = 8.0; 95% CI 3.1 - 21.2). Among current smokers, 32% were classified as regular smokers and 18% as social smokers. Sixty-three percent of regular smokers and 42% of social smokers reported smoking within 30 minutes of waking, an indicator of nicotine dependence. Patterns of smoking were variable in rate and frequency ranging from 1 to 30 cigarettes per day. Current female smokers scored higher on the modified Beck Depression Inventory (0-3) than current male smokers (p < 0.001). Oral health issues related to tobacco use, such as gum disease and tooth staining, were identified as factors that might motivate a quit attempt. Frequently reported reasons for use (eg, tension and craving) and reasons for relapse (eg, desire remained high, withdrawal symptoms) were related to nicotine dependence. Fifty-three percent of all smokers had tried to stop smoking but were unsuccessful. Intrapersonal characteristics such as risk-taking, rebellion, and impulsive spending appeared to be related to smoking. CONCLUSION: In this sample of adolescents, smoking patterns were variable and many adolescents experienced symptoms of nicotine dependence. The dental hygiene care appointment provides a unique opportunity to discuss oral health effects of smoking, relate oral changes to smoking, and to deliver a brief smoking cessation intervention.

Adolescent↗
PubMed2005

A prospective randomised controlled trial of VNUS closure versus surgery for the treatment of recurrent long saphenous varicose veins.

OBJECTIVE: This study aimed to assess the outcome of endoluminal thermal ablation (VNUS) and traditional redo groin surgery (RGS) and long saphenous vein (LSV) stripping in patients with bilateral recurrent long saphenous varicose veins. METHODS: This was a randomised patient controlled double blind study. Sample size calculations required 16 patients. Their median age was 54 and 11 were women. The median CEAP class was 3. At operation one leg, chosen at random, was treated with VNUS and avulsions using intra-operative duplex control. The other leg was treated with traditional RGS, exposure of the femoral vein, stripping of the LSV and multiple avulsions. Post-operatively patients completed 10 cm visual analogue scales for pain and bruising. Digital Image analysis was used to objectively assess bruising. Statistical analysis was done using Wilcoxon signed rank test for paired data. Results are expressed as median values (inter-quartile ranges). RESULTS: Time to perform VNUS was 25.5 (20.5-31.3) min compared with 40 (34.5-45.5) min it took for RGS (p=0.02). Pain score for VNUS was 1.7 (0.2-4), significantly lower than that for RGS 3.8 (0.6-6.3) (p=0.02). Bruise score for VNUS was 1.7 (0.4-4.4), and that for RGS was 5.2 (2.6-7) (p=0.03). All LSVs were sealed by VNUS at duplex follow up. Three legs in the RGS group and two in the VNUS group had a minor complication. CONCLUSIONS: VNUS caused less pain and bruising and was performed more quickly than RGS. VNUS should be considered the treatment of choice for recurrent long saphenous varicose veins.

Adult↗
PubMed2004

A precision measurement of the mass of the top quark.

The standard model of particle physics contains parameters--such as particle masses--whose origins are still unknown and which cannot be predicted, but whose values are constrained through their interactions. In particular, the masses of the top quark (M(t)) and W boson (M(W)) constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of M(t) can therefore indicate where to look for the Higgs, and indeed whether the hypothesis of a standard model Higgs is consistent with experimental data. As top quarks are produced in pairs and decay in only about 10(-24) s into various final states, reconstructing their masses from their decay products is very challenging. Here we report a technique that extracts more information from each top-quark event and yields a greatly improved precision (of +/- 5.3 GeV/c2) when compared to previous measurements. When our new result is combined with our published measurement in a complementary decay mode and with the only other measurements available, the new world average for M(t) becomes 178.0 +/- 4.3 GeV/c2. As a result, the most likely Higgs mass increases from the experimentally excluded value of 96 to 117 GeV/c2, which is beyond current experimental sensitivity. The upper limit on the Higgs mass at the 95% confidence level is raised from 219 to 251 GeV/c2.

Journal Article↗
PubMed2004

Search for narrow tt resonances in pp collisions at square root of (s)=1.8 TeV.

A search for narrow resonances that decay into tt pairs has been performed using 130 pb(-1) of data in the lepton + jets channel collected by the Dphi detector in pp collisions at square root of (s)=1.8 TeV. There is no significant deviation observed from the standard-model predictions at a top-quark mass of 175 GeV/c2. We therefore present upper limits at the 95% confidence level on the product of the production cross section and branching fraction to tt for narrow resonances as a function of the resonance mass MX. These limits are used to exclude the existence of a leptophobic top-color particle with mass MX<560 GeV/c2, using a theoretical cross section for a width GammaX=0.012MX.

Journal Article↗
PubMed2004

A validated PCR-based method to detect Listeria monocytogenes using raw milk as a food model--towards an international standard.

A PCR assay with an internal amplification control was developed for Listeria monocytogenes. The assay has a 99% detection probability of seven cells per reaction. When tested against 38 L. monocytogenes strains and 52 nontarget strains, the PCR assay was 100% inclusive (positive signal from target) and 100% exclusive (no positive signal from nontarget). The assay was then evaluated in a collaborative trial involving 12 European laboratories, where it was tested against an additional 14 target and 14 nontarget strains. In that trial, the inclusivity was 100% and the exclusivity was 99.4%, and both the accordance (repeatability) and the concordance (reproducibility) were 99.4%. The assay was incorporated within a method for the detection of L. monocytogenes in raw milk, which involves 24 h of enrichment in half-Fraser broth followed by 16 h of enrichment in a medium that can be added directly into the PCR. The performance characteristics of the PCR-based method were evaluated in a collaborative trial involving 13 European laboratories. In that trial, a specificity value (percentage of correct identification of blank samples) of 81.8% was obtained; the accordance was 87.9%, and the concordance was 68.1%. The sensitivity (correct identification of milk samples inoculated with 20 to 200 L. monocytogenes cells per 25 ml) was 89.4%, the accordance was 81.2%, and the concordance was 80.7%. This method provides a basis for the application of routine PCR-based analysis to dairy products and other foodstuffs and should be appropriate for international standardization.

Animals↗
PubMed2002

A nucleic acid sequence-based amplification method to detect Salmonella enterica serotype enteritidis strain PT4 in liquid whole egg.

Nucleic acid sequence-based amplification (NASBA) was applied to the detection of Salmonella enterica cells in liquid whole egg. Samples (25 g) of liquid whole egg inoculated with Salmonella cells were enriched for 16 h in buffered peptone water, and the NASBA procedure was effective in detecting the presence of Salmonella in samples inoculated with 10 to 100 CFU prior to enrichment.

Animals↗
PubMed2001

Quasi-model-independent search for new high p(T) physics at D0.

We apply a quasi-model-independent strategy ("Sleuth") to search for new high p(T) physics in approximately 100 pb(-1) of pp collisions at square root of (s) = 1.8 TeV collected by the D0 experiment during 1992-1996 at the Fermilab Tevatron. We systematically analyze many exclusive final states and demonstrate sensitivity to a variety of models predicting new phenomena at the electroweak scale. No evidence of new high p(T) physics is observed.

Journal Article↗
PubMed2001

Ratio of jet cross sections at square root of s = 630 GeV and 1800 GeV.

The D0 Collaboration has measured the inclusive jet cross section in barpp collisions at square root of s = 630 GeV. The results for pseudorapidities (eta)<0.5 are combined with our previous results at square root of s = 1800 GeV to form a ratio of cross sections with smaller uncertainties than either individual measurement. Next-to-leading-order QCD predictions show excellent agreement with the measurement at 630 GeV; agreement is also satisfactory for the ratio. Specifically, despite a 10% to 15% difference in the absolute magnitude, the dependence of the ratio on jet transverse momentum is very similar for data and theory.

Journal Article↗
PubMed2001

Ratios of multijet Cross Sections in p p collisions at radical(s) = 1.8 TeV.

We report on a study of the ratio of inclusive three-jet to inclusive two-jet production cross sections as a function of total transverse energy in p&pmacr; collisions at a center-of-mass energy sqrt[s] = 1.8 TeV, using data collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. The measurements are used to deduce preferred renormalization scales in perturbative O(alpha(3)(s)) QCD calculations in modeling soft-jet emission.

Journal Article↗
PubMed2001

Inclusive jet production in pp(macro) collisions.

We report a new measurement of the pseudorapidity (eta) and transverse-energy ( E(T)) dependence of the inclusive jet production cross section in pp(macro) collisions at square root of s = 1.8 TeV using 95 pb(-1) of data collected with the D0 detector at the Fermilab Tevatron. The differential cross section d(2)sigma/(dE(T)d eta) is presented up to eta = 3, significantly extending previous measurements. The results are in good overall agreement with next-to-leading order predictions from QCD and indicate a preference for certain parton distribution functions.

Journal Article↗
PubMed2001

Search for large extra dimensions in dielectron and diphoton production.

We report a search for effects of large extra spatial dimensions in pp collisions at a center-of-mass energy of 1.8 TeV with the D0 detector, using events containing a pair of electrons or photons. The data are in good agreement with the expected background and do not exhibit evidence for large extra dimensions. We set the most restrictive lower limits to date, at the 95% C.L. on the effective Planck scale between 1.0 and 1.4 TeV for several formalisms and numbers of extra dimensions.

Journal Article↗
PubMed2001

Thromboprophylaxis following caesarean section--a comparison of the antithrombotic properties of three low molecular weight heparins--dalteparin, enoxaparin and tinzaparin.

Pharmacological thromboprophylaxis is increasingly being used after caesarean section to prevent venous thromboembolism. Although a variety of low molecular weight heparins (LMWH) have been used no comparative study exists on their effects on the haemostatic system in this situation. Furthermore, their antithrombotic effect may be mediated through effects other than their inhibitory effect on activated factor X. We compared the plasma anti-factor Xa activity, plasma concentration of tissue factor pathway inhibitor (TFPI) and the reduction in plasma thrombin-antithrombin (TAT) complex concentration in 30 women randomised to receive either dalteparin 5,000 IU anti-Xa once daily (n = 10), enoxaparin 4,000 IU anti-Xa once daily (n = 10) or tinzaparin 50 IU/kg anti-Xa (average dose 3,650 anti-Xa units) once daily (n = 10) following caesarean section. Sampling occurred at 0, 1, 3, 6, 12 and 24 h relative to time of dosing. All preparations produced an increase in mean anti-Xa assay (p < 0.0001), a reduction in mean TAT (p < 0.05) and an increase in mean TFPI concentration (p <0.05). Analysis of variance (ANOVA) revealed a significant difference between the LMWHs in terms of mean anti-factor Xa activity (p < 0.005) and reduction in plasma TAT concentration (p < 0.005). Post hoc analysis indicated that the anti-Xa values of the groups receiving enoxaparin and dalteparin were significantly higher than those of the group receiving tinzaparin (p < 0.05), but not significantly different from each other. Post hoc analysis of the reduction in plasma TAT concentration showed the reduction to be significantly less in the group receiving enoxaparin compared to the dalteparin and tinzaparin groups (p < 0.05), which did not differ significantly from each other. There was no significant difference between treatment groups with regard to plasma concentration of TFPI. These findings demonstrate that LMWHs differ in their effects on haemostatic parameters including thrombin generation as assessed by TAT. The increase in TFPI may be an additional mediator of LMWH's antithrombotic effects. Although these findings demonstrate that LMWHs differ in their haemostatic effects, this does not necessarily infer a clinical difference between these agents.

Adolescent↗
PubMed2000

Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV.

We report on a measurement of sigma(pp-->W+X)B(W-->taunu) in pp collisions at sqrt[s]=1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of 18 pb-1 of data collected with the D0 detector during 1994-1995. We find that sigma(pp-->W+X)B(W-->taunu)=2.22+/-0.09 (stat)+/-0. 10 (syst)+/-0.10 (lum) nb. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the W boson, gWtau/gWe, be unity. We find gWtau/gWe=0.980+/-0.031, in agreement with lepton universality.

Journal Article↗
PubMed2000

Probing Balitsky-Fadin-Kuraev-Lipatov dynamics in the dijet cross section at large rapidity intervals in pp collisions at sqrt[s]=1800 and 630 GeV.

Inclusive dijet production at large pseudorapidity intervals (Deltaeta) between the two jets has been suggested as a regime for observing Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. We have measured the dijet cross section for large Deltaeta in pp collisions at sqrt[s]=1800 and 630 GeV using the D0 detector. The partonic cross section increases strongly with the size of Deltaeta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alphaBFKL(20 GeV)=1.65+/-0.07.

Journal Article↗
PubMed2000

Prevalence of the post-thrombotic syndrome in young women with previous venous thromboembolism.

The prevalence of mild, moderate and severe post-thrombotic syndrome (PTS) among 43 young women with a previous single episode of deep vein thrombosis (DVT) was 67%, 7% and 0% respectively. Subjects were assessed at a mean 51 months after the event. Moderate PTS was more common in women with recurrent (n = 9) DVT (44%, P < 0.001). Chronic venous insufficiency, assessed by light reflection rheography (LRR), was significantly (P < 0.05) more prevalent in women with single previous DVT (n = 40), recurrent DVT (n = 9) and isolated pulmonary embolism (PE) (n = 19) compared with healthy age-matched controls (odds ratios 10.9, 52.4 and 3.8 respectively). LRR findings correlated with moderate, but not mild, PTS. There was no correlation between development of PTS and body mass index.

Adolescent↗