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Biomedical subjects

D Jenkins

Publications and source records attributed to D Jenkins.

At least 19 recordsLinked to original sources

Uroplakins: new molecular players in the biology of urinary tract malformations.

The uroplakins (UPs) are a family of proteins which associate with each other and form plaques on the apical surface of the urothelium. These plaques contribute to a permeability barrier, preventing the influx of urine from the urinary tract lumen. Urinary tract malformations associated with human and mouse UP mutations, the human fetal expression patterns of UPs and experiments in Xenopus oocytes are collectively revealing new functions for the UPs, forcing us to view these proteins in a new light. Rather than simply being products of the urothelial differentiation program, they may be a group of proteins central to the process of urinary tract differentiation itself.

Animals↗

Estimating the long-term impact of a prophylactic human papillomavirus 16/18 vaccine on the burden of cervical cancer in the UK.

To predict the public health impact on cervical disease by introducing human papillomavirus (HPV) vaccination in the United Kingdom, we developed a mathematical model that can be used to reflect the impact of vaccination in different countries with existing screening programmes. Its use is discussed in the context of the United Kingdom. The model was calibrated with published data. The impact of vaccination on cervical cancer and deaths, precancerous lesions and screening outcomes were estimated for a vaccinated cohort of 12-year-old girls, among which it is estimated that there would be a reduction of 66% in the prevalence of high-grade precancerous lesions and a 76% reduction in cervical cancer deaths. Estimates for various other measures of the population effects of vaccination are also presented. We concluded that it is feasible to forecast the potential effects of HPV vaccination in the context of an existing national screening programme. Results suggest a sizable reduction in the incidence of cervical cancer and related deaths. Areas for future research include investigation of the beneficial effects of HPV vaccination on infection transmission and epidemic dynamics, as well as HPV-related neoplasms in other sites.

Calibration↗

Measurement of the N-->Delta(+)(1232) transition at high-momentum transfer by pi(0) electroproduction.

We report a new measurement of the exclusive electroproduction reaction gamma(*)p-->pi(0)p to explore the evolution from soft nonperturbative physics to hard processes via the Q(2) dependence of the magnetic (M(1+)), electric (E(1+)), and scalar (S(1+)) multipoles in the N-->Delta transition. 9000 differential cross section data points cover W from threshold to 1.4 GeV/c(2), 4pi center-of-mass solid angle, and Q(2) from 3 to 6 GeV(2)/c(2), the highest yet achieved. It is found that the magnetic form factor G(M)(*) decreases with Q(2) more steeply than the proton magnetic form factor, the ratio E(1+)/M(1+) is small and negative, indicating strong helicity nonconservation, and the ratio S(1+)/M(1+) is negative, while its magnitude increases with Q(2).

Journal Article↗

Search for Theta++ pentaquarks in the exclusive reaction gammap-->K+K-p.

The reaction gammap --> pK+K- was studied at Jefferson Lab with photon energies from 1.8 to 3.8 GeV using a tagged photon beam. The goal was to search for a Theta++ pentaquark, a narrow, doubly charged baryon state having strangeness S=+1 and isospin I=1, in the pK+ invariant mass spectrum. No statistically significant evidence of a Theta++ was found. Upper limits on the total and differential cross section for the reaction gammap --> K-Theta++ were obtained in the mass range from 1.5 to 2.0 GeV/c2, with an upper limit for a narrow resonance with a mass M(Theta++) = 1.54 GeV/c2 of about 0.15 nb, 95% C.L.. This result places a stringent upper limit on the Theta++ width Gamma(Theta++) <0.1 MeV/c2.

Journal Article↗

Search for the Theta+ Pentaquark in the gammad--> DeltanK+ reaction measured with the CLAS spectrometer.

For the first time, the reaction gammad-->DeltanK+ has been analyzed in order to search for the exotic pentaquark baryon Theta+(1540). The data were taken at Jefferson Laboratory, using the Hall-B tagged-photon beam of energy between 0.8 and 3.6 GeV and the CEBAF Large Acceptance Spectrometer (CLAS). No statistically significant structures were observed in the nK+ invariant-mass distribution. The upper limit on the gammad-->DeltaTheta+ integrated cross section has been calculated and found to be between 5 and 25 nb, depending on the production model assumed. The upper limit on the differential cross section is also reported.

Journal Article↗

Search for the Theta+ pentaquark in the reaction gammad --> pK-K+n.

A search for the Theta+ in the reaction gammad --> pK-K+n was completed using the CLAS detector at Jefferson Lab. A study of the same reaction, published earlier, reported the observation of a narrow Theta+ resonance. The present experiment, with more than 30 times the integrated luminosity of our earlier measurement, does not show any evidence for a narrow pentaquark resonance. The angle-integrated upper limit on Theta+ production in the mass range of 1.52-1.56 GeV/c2 for the gammad --> pK-Theta+ reaction is 0.3 nb (95% C.L.). This upper limit depends on assumptions made for the mass and angular distribution of Theta+ production. Using Lambda(1520) production as an empirical measure of rescattering in the deuteron, the cross section upper limit for the elementary gamman --> K-Theta+ reaction is estimated to be a factor of 10 higher, i.e., approximately 3 nb (95% C.L.).

Journal Article↗

Measurement of two- and three-nucleon short-range correlation probabilities in nuclei.

The ratios of inclusive electron scattering cross sections of 4He, 12C, and 56Fe to 3He have been measured at 1 < xB <. At Q2 > 1.4 GeV2, the ratios exhibit two separate plateaus, at 1.5 < xB < 2 and at xB > 2.25. This pattern is predicted by models that include 2- and 3-nucleon short-range correlations (SRC). Relative to A = 3, the per-nucleon probabilities of 3-nucleon SRC are 2.3, 3.1, and 4.4 times larger for A = 4, 12, and 56. This is the first measurement of 3-nucleon SRC probabilities in nuclei.

Journal Article↗

Search for Theta+ (1540) Pentaquark in High-Statistics Measurement of gammap-->K0K+n at CLAS.

The exclusive reaction gammap-->K0K+n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of the exotic baryon Theta+ (1540)-->nK+. The decay to nK+requires the assignment of strangeness S=+1 to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70 pb-1. No evidence for the Theta+ pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and nK+ mass. The 95% C.L. upper limit on the total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb.

Journal Article↗

The impact of anti-tumour necrosis factor therapy for rheumatoid arthritis on the use of other drugs and hospital resources in a pragmatic setting.

BACKGROUND: Anti-tumour necrosis factor (anti-TNF) therapy has been an important development for the treatment of rheumatoid arthritis (RA) but the impact of its delivery on hospital resources in still emerging. AIMS: We audited the effect of starting anti-TNF on the use of other anti-rheumatic therapies and hospital resources in a routine secondary care setting. METHODS: A retrospective study of resource use before and after anti-TNF was conducted. Hospital records of 54 RA patients were studied and data taken from the time of commencing anti-TNF to 1 October 2004 and an equal time period prior to commencing anti-TNF. Identical data were collected for 54 controls not on anti-TNF. Relevant figures were extrapolated to per annum rates. Results were analysed using two-factor ANOVAs comparing the pre- versus post-anti-TNF period. Cases on intravenous (IV) versus subcutaneous (SC) anti-TNF were also compared in separate ANOVAs. RESULTS: Mean duration of anti-TNF therapy was 17.04 months (range 3.60-42.36). Mean pre- and 3-months post-anti-TNF Disease Activity Scores (DAS28) were 6.93 and 3.88, respectively. Cases were more likely than controls to be on oral prednisolone pre- and post-anti-TNF. Methylprednisolone requirement, number of disease-modifying anti-rheumatic drugs (DMARDs), telephone helpline contacts and duration as an inpatient reduced significantly post-anti-TNF. Day case admissions increased but outpatient appointments decreased only in cases on IV anti-TNF. CONCLUSIONS: In a pragmatic setting, anti-TNF therapy led to reduced need for steroid injections and other DMARDs, as well as reductions in use of several hospital resources. Wider replication of these findings will be important for planning delivery.

Adult↗

Methicillin-resistant Staphylococcus aureus on orthopaedic wards: incidence, spread, mortality, cost and control.

We examined the rates of infection and colonisation by methicillin-resistant Staphylococcus aureus (MRSA) between January 2003 and May 2004 in order to assess the impact of the introduction of an MRSA policy in October 2003, which required all admissions to be screened. Emergency admissions were treated prophylactically and elective beds ring-fenced. A total of 5,594 admissions were cross-referenced with 22,810 microbiology results. The morbidity, mortality and cost of managing MRSA-carrying patients, with a proximal fracture of the femur were compared, in relation to age, gender, American Society of Anaesthesiologists grade and residential status, with a group of matched controls who were MRSA-negative. In 2004, we screened 1795 of 1,796 elective admissions and MRSA was found in 23 (1.3%). We also screened 1,122 of 1,447 trauma admissions and 43 (3.8%) were carrying MRSA. All ten ward transfers were screened and four (40%) were carriers (all p < 0.001). The incidence of MRSA in trauma patients increased by 2.6% per week of inpatient stay (r = 0.97, p < 0.001). MRSA developed in 2.9% of trauma and 0.2% of elective patients during that admission (p < 0.001). The implementation of the MRSA policy reduced the incidence of MRSA infection by 56% in trauma patients (1.57% in 2003 (17 of 1,084) to 0.69% in 2004 (10 of 1,447), p = 0.035). Infection with MRSA in elective patients was reduced by 70% (0.56% in 2003 (7 of 1,257) to 0.17% in 2004 (3 of 1,806), p = 0.06). The cost of preventing one MRSA infection was 3,200 pounds. Although colonisation by MRSA did not affect the mortality rate, infection by MRSA more than doubled it. Patients with proximal fractures of the femur infected with MRSA remained in hospital for 50 extra days, had 19 more days of vancomycin treatment and 26 more days of vacuum-assisted closure therapy than the matched controls. These additional costs equated to 13,972 pounds per patient. From this experience we have been able to describe the epidemiology of MRSA, assess the impact of infection-control measures on MRSA infection rates and determine the morbidity, mortality and economic cost of MRSA carriage on trauma and elective orthopaedic wards.

Adult↗

Evidence for nontermination of rotational bands in 74Kr.

Three rotational bands in 74Kr were studied up to (in one case one transition short of) the maximum spin I(max) of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I(max). This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I = I(max).

Journal Article↗

Beam-helicity asymmetries in double-charged-pion photoproduction on the proton.

Beam-helicity asymmetries for the two-pion-photoproduction reaction gammap-->ppi(+)pi(-) have been studied for the first time in the resonance region for center-of-mass energies between 1.35 and 2.30 GeV. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer using circularly polarized tagged photons incident on an unpolarized hydrogen target. Beam-helicity-dependent angular distributions of the final-state particles were measured. The large cross-section asymmetries exhibit strong sensitivity to the kinematics and dynamics of the reaction. The data are compared with the results of various phenomenological model calculations, and show that these models currently do not provide an adequate description for the behavior of this new observable.

Journal Article↗

Human papillomavirus infection in women who develop high-grade cervical intraepithelial neoplasia or cervical cancer: a case-control study in the UK.

Human papillomavirus (HPV) testing might identify older women who could be withdrawn from the cervical screening programme, or require less frequent screening. A case-control study using the United Kingdom cervical screening population was set up to help address this issue. Cases comprised 575 women who developed cervical intraepithelial neoplasia (CIN) grade 2 or worse over a 13-year period following a cytologically normal baseline smear, and were stratified by age group ('under 20', '20-39' and 40 years or over). Controls (n=601) were women who remained disease free over this interval and were the same age on average as cases. DNA was extracted from the baseline smears and tested for HPV by PCR using GP5+/6+ consensus primers. HPV+ samples were tested for HPV types 16 and 18 using specific PCR primers. In all, 27.0% of cases tested positive for HPV at baseline, compared with 15.4% of controls (odds ratio (OR)=2.00; 95% confidence interval (CI), 1.50-2.68). Among women aged 40 years or over, the OR for HPV 16 was 8.95 (95% CI, 2.63-30.4). These results support the need for further cervical screening of HPV- older women, as many of the cases were HPV- at baseline.

Adult↗

Onset of asymptotic scaling in deuteron photodisintegration.

We investigate the transition from the nucleon-meson to the quark-gluon description of the strong interaction using the photon energy dependence of the d(gamma,p)n differential cross section for photon energies above 0.5 GeV and center-of-mass proton angles between 30 degrees and 150 degrees. A possible signature for this transition is the onset of cross-section s(-11) scaling with the total energy squared, s, at some proton transverse momentum P(T). The results show that the scaling has been reached for proton transverse momentum above about 1.1 GeV/c. This may indicate that the quark-gluon regime is reached above this momentum.

Journal Article↗

CHHIPS (Controlling Hypertension and Hypotension Immediately Post-Stroke) Pilot Trial: rationale and design.

RATIONALE: High and low blood pressure (BP) levels are common following acute stroke, with up to 60% of patients being hypertensive (SBP > 160 mmHg) and nearly 20% having relative hypotension (SBP < or = 140 mmHg), within the first few hours of ictus, both conditions being associated with an adverse prognosis. At present, the optimum management of blood pressure in the immediate post-stroke period is unclear. OBJECTIVE: The primary aim of the Controlling Hypertension and Hypotension Immediately Post-Stroke (CHHIPS) Pilot Trial is to assess whether hypertension and relative hypotension, manipulated therapeutically in the first 24 h following acute stroke, affects short-term outcome measures. DESIGN: The CHHIPS Pilot Trial is a UK based multi-centre, randomized, double-blind, placebo-controlled, titrated dose trial. SETTING: Acute stroke and medical units in teaching and district general hospitals, in the UK. PATIENTS: The CHHIPS Pilot Study aims to recruit 2050 patients, with clinically suspected stroke, confirmed by brain imaging, who have no compelling indication or contraindication for BP manipulation. STUDY OUTCOMES: The primary outcome measure will be the effects of acute pressor therapy (initiated < or = 12 h from stroke onset) or depressor therapy (started < or = 24 h post-ictus) on death and dependency at 14 days post-stroke. Secondary outcome measures will include the influence of therapy on early neurological deterioration, the effectiveness of treatment in manipulating BP levels, the influence of time to treatment and stroke type on response and a cost-effectiveness analysis.

Acute Disease↗

Drowning of babies in bath seats: do they provide false reassurance?

AIMS: To investigate the problem of children drowning in bath seats by examining case reports, by looking at the epidemiology of bath drowning in children under two years of age and by reviewing the literature. METHODS: We describe two babies: one who drowned and one nearly drowned in the bath whilst in a bath seat. We examined the RoSPA/RLSS UK database of cases of children under two years drowning in the bath for the years 1989-2003. Cases are ascertained through a press cutting system. We conducted an all language literature search of original articles, references, textbooks and conference abstracts 1951-October 2004 in 11 standard databases. RESULTS: The two cases illustrate how parents can have a false sense of security with bath seats. We found six cases of babies under two years drowning in the UK associated with bath seats in the time period 1989-2003. They were all boys: five of the six were under one year of age. This compared with 47 children of similar age drowning in the bath not associated with a bath seat. The literature is sparse with only four papers since 1966. DISCUSSION: A baby drowning after being placed in a bath seats is a rare but definite cause of death. Bath seats appear to give a false sense of security (even if not encouraged by the manufacturers). It is unclear whether putting a baby in a bath seat represents an increased risk of drowning compared with a baby without a seat. Without knowing the numbers of mothers that use bath seats it is difficult to come to firm conclusions on the risks to babies. New research is needed to clarify this issue. Whether in a seat or not it is clear that the main risk to babies in the bath is being left unsupervised.

Drowning↗

Proton source size measurements in the eA-->e'ppX reaction.

Two-proton correlations at small relative momentum q were studied in the eA(3He,4He,C,Fe)-->e(')ppX reaction at E(0)=4.46 GeV using the CLAS detector at Jefferson Lab. The enhancement of the correlation function at small q was found to be in accordance with theoretical expectations. Sizes of the emission region were extracted, and proved to be dependent on A and on the proton momentum. The size of the two-proton emission region for He was measured in eA reactions for the first time.

Journal Article↗