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Biomedical subjects

J Graham

Publications and source records attributed to J Graham.

At least 55 records · Page 3Linked to original sources
PubMed2001

First measurement of form factors of the decay Xi(0) --> Sigma(+)e(-)nu macro(e).

We present the first measurement of the form factor ratios g(1)/f(1) (direct axial vector to vector), g(2)/f(1) (second class current), and f(2)/f(1) (weak magnetism) for the decay Xi(0)-->Sigma(+)e(-)nu macro(e) using the KTeV (E799) beam line and detector at Fermilab. From the Sigma(+) polarization measured with the decay Sigma(+)-->p pi(0) and the e(-)-nu; correlation, we measure g(1)/f(1) to be 1.32+/-(0.21)(0.17)(stat)+/-0.05(syst), assuming the SU(3)(f) (flavor) values for g(2)/f(1) and f(2)/f(1). Our results are all consistent with exact SU(3)(f) symmetry.

Journal Article↗
PubMed2001

Branching ratio measurement of the decay K(L) --> e(+)e(-)mu(+)mu(-).

We have collected a 43 event sample of the decay K(L)-->e(+)e(-)mu(+)mu(-) with negligible backgrounds and measured its branching ratio to be (2.62+/-0.40+/-0.17)x10(-9). We see no evidence for CP violation in this decay. In addition, we set the 90% confidence upper limit on the combined branching ratios for the lepton flavor violating decays K(L)-->e(+/-)e(+/-)mu(-/+)mu(-/+) at B(K(L)-->e(+/-)e(+/-)mu(-/+)mu(-/+))< or =1.23x10(-10), assuming a uniform phase space distribution.

Journal Article↗
PubMed2001

Measurement of the branching ratio and form factor of K(L)-->mu(+)mu(-)gamma.

We report on the analysis of the rare decay K(L)-->mu(+)mu(-)gamma the 1997 data from the KTeV experiment at Fermilab. A total of 9327 candidate events are observed with 2.4% background, representing a factor of 40 increase in statistics over the current world sample. We find that B(K(L)-->mu(+)mu(-)gamma) = (3.62 +/- 0.04(stat) +/- 0.08(syst)) x 10(-7). The form factor parameter alpha(K*) is measured to be alpha(K*) = -0.160(+0.026)(-0.028). In addition, we make the first measurement of the parameter alpha from the D'Ambrosio-Isidori-Portolés form factor, finding alpha = -1.54 +/- 0.10. In that model, this alpha measurement limits the Cabibbo-Kobayashi-Maskawa parameter rho>-0.2.

Journal Article↗
PubMed2001

Measurements of the rare decay K(L) --> e(+)e(-)e(+)e(-).

We observe 441 K(L)-->e(+)e(-)e(+)e(-) candidate events with a background of 4.2 events and measure B(K(L)-->e(+)e(-)e(+)e(-)) = [3.72+/-0.18(stat)+/-0.23(syst)]x10(-8) in the KTeV/E799II experiment at Fermilab. Using the distribution of the angle between the planes of the e(+)e(-) pairs, we measure the CP parameters beta(CP) = -0.23+/-0.09(stat)+/-0.02(syst) and gamma(CP) = -0.09+/-0.09(stat)+/-0.02(syst). We also present the first detailed study of the e(+)e(-) invariant mass spectrum in this decay mode.

Journal Article↗
PubMed2001

Measurement of the branching ratio and asymmetry of the decay Xi degrees -->Sigma degrees gamma.

We have studied the rare weak radiative hyperon decay Xi degrees -->Sigma degrees gamma in the KTeV experiment at Fermilab. We have identified 4045 signal events over a background of 804 events. The dominant Xi degrees -->Lambdapi degrees decay, which was used for normalization, is the only important background source. An analysis of the acceptance of both modes yields a branching ratio of B(Xi degrees -->Sigma degrees gamma)/B(Xi degrees -->Lambdapi degrees ) = (3.34+/-0.05+/-0.09)x10(-3). By analyzing the final state decay distributions, we have also determined that the Sigma degrees emission asymmetry parameter for this decay is alpha(XiSigma) = -0.63+/-0.09.

Journal Article↗
PubMed2001

Evidence for a replication function of FFA-1, the Xenopus orthologue of Werner syndrome protein.

DNA replication in higher eukaryotic cells occurs at a large number of discrete sites called replication foci. We have previously purified a protein, focus-forming activity 1 (FFA-1), which is involved in the assembly of putative prereplication foci in Xenopus egg extracts. FFA-1 is the orthologue of the Werner syndrome gene product (WRN), a member of the RecQ helicase family. In this paper we show that FFA-1 colocalizes with sites of DNA synthesis and the single-stranded DNA binding protein, replication protein A (RPA), in nuclei reconstituted in the egg extract. In addition, we show that two glutathione S-transferase FFA-1 fusion proteins can inhibit DNA replication in a dominant negative manner. The dominant negative effect correlates with the incorporation of the fusion proteins into replication foci to form "hybrid foci," which are unable to engage in DNA replication. At the biochemical level, RPA can interact with FFA-1 and specifically stimulates its DNA helicase activity. However, in the presence of the dominant negative mutant proteins, the stimulation is prevented. These results provide the first direct biochemical evidence of an important role for FFA-1 in DNA replication.

Adenosine Triphosphatases↗
PubMed2001

The relationships between post-prandial lipaemia, endothelial function and oxidative stress in healthy individuals and patients with type 2 diabetes.

Post-prandial lipaemia (PPL) is a factor in atherogenesis and results in reversible endothelial dysfunction in healthy individuals. Oxidative stress and triglyceride (TG)-rich lipoproteins have been implicated. Type 2 diabetes (NIDDM) results in exaggerated PPL. We attempted to delineate the mechanisms of PPL induced, endothelial dysfunction (EF) and oxidative stress in 12 NIDDM and 12 matched healthy subjects. Subjects underwent a fat tolerance test, with endothelial function assessed by flow-mediated vasodilatation and oxidative stress measured by venous lipid-derived free radicals ex vivo and lipid peroxidation products over the postprandial phase. Fasting TG, post-prandial hypertriglyceridaemia and the TG enrichment of all lipoproteins was significantly greater in NIDDM. Post-prandial endothelial function inversely correlated with fasting HDL-C (r=-0.84, P=0.001) in both the control and NIDDM groups. The deterioration in EF in the NIDDM group also correlated with TG enrichment of VLDL and LDL. PPL in both groups also resulted in increased oxidative stress. The increment in free radicals correlated with TG enrichment of VLDL in both groups and was, therefore, greater in NIDDM. Thus, PPL -- with the production of TG-enrichment of VLDL -- results in endothelial dysfunction by an oxidative stress mechanism in both groups. The magnitude is greater in NIDDM. Fasting HDL-C appears to contribute to the protection of the endothelium against this phenomenon. Hence, exaggerated PPL associated with reduced HDL-C may be important in the pathogenesis of vascular disease, particularly in NIDDM.

Adult↗
PubMed2001

Study of the K(0)(L) --> pi(+)pi(-)gamma Direct Emission Vertex.

We have performed studies of the K(0)(L)-->pi(+)pi(-)gamma direct emission ( DE) and inner Bremsstrahlung ( IB) vertices, based on data collected by KTeV during the 1996 Fermilab fixed target run. We find a(1)/a(2) = -0.737+/-0.034 GeV2 for the DE form-factor parameter in the rho-propagator parametrization, and report on fits of the form factor to linear and quadratic functions as well. We concurrently measure gamma(K(0)(L)-->pi(+)pi(-)gamma,E(*)(gamma)>20 MeV)/gamma(K(0)(L)-->pi(+)pi(-)) = (20.8+/-0.3)x10(-3), and a K(0)(L)-->pi(+)pi(-)gamma DE/(DE+IB) branching ratio of 0.683+/-0.011.

Journal Article↗
PubMed2001

Search for the decay KL --> pi(0)e+e-.

We report on a search for the decay KL-->pi(0)e+e- carried out by the KTeV/E799 experiment at Fermilab. This decay is expected to have a significant CP violating contribution and the measurement of its branching ratio could support the Cabibbo-Kobayashi-Maskawa mechanism for CP violation or could point to new physics. Two events were observed in the 1997 data with an expected background of 1.06+/-0.41 events, and we set an upper limit B(KL-->pi(0)e+e-)<5.1 x 10(-10) at the 90% confidence level.

Journal Article↗
PubMed2001

Effectiveness of an intervention to reduce HIV transmission risks in HIV-positive people.

BACKGROUND: As many as one in three HIV-positive people continue unprotected sexual practices after learning that they are HIV infected. This article reports the outcomes of a theory-based intervention to reduce risk of HIV transmission for people living with HIV infection. METHODS: Men (n=233) and women (n=99) living with HIV-AIDS were randomly assigned to receive either (1) a five-session group intervention focused on strategies for practicing safer sexual behavior, or (2) a five-session, contact-matched, health-maintenance support group (standard-of-care comparison). Participants were followed for 6 months post-intervention. RESULTS: The intervention to reduce risk of HIV transmission resulted in significantly less unprotected intercourse and greater condom use at follow-up. Transmission-risk behaviors with non-HIV-positive sexual partners and estimated HIV transmission rates over a 1-year horizon were also significantly lower for the behavioral risk-reduction intervention group. CONCLUSIONS: This study is among the first to demonstrate successful HIV-transmission risk reduction resulting from a behavioral intervention tailored for HIV-positive men and women.

Adaptation, Psychological↗
PubMed2001

Consulting about consulting: challenges to effective consulting about public health research.

OBJECTIVE: To understand barriers to obtaining input from consumers in developing public health research. METHODS: Documentation of a failed attempt at consumer consultation supplies information on barriers to effective involvement and conditions that must prevail to improve consultation. RESULTS: People are keen to be heard in the formulation of health research. However, competing demands and limited resources make it difficult for community groups to allocate scarce resources to consultation. Sometimes research issues may seem 'academic' and thus remote from the urgent priorities of the people with whom researchers wish to consult. Consultation may require more time than researchers on limited budgets can afford. CONCLUSIONS: Despite a general public health commitment to involving consumers in research development, obstacles to consultation make it difficult to incorporate it into the research agenda. IMPLICATIONS: Researchers and funding bodies will need to allocate resources to consumer consultation if it is to become the rule rather than the exception in public health research.

Australia↗
PubMed2001

Chryseobacterium (Flavobacterium) meningosepticum outbreak associated with colonization of water taps in a neonatal intensive care unit.

From September 1994 to May 1996, a strain of multi-resistant Chryseobacterium (Flavobacterium) meningosepticum was isolated from eight neonates on a neonatal intensive care unit. The strain was resistant to ampicillin, ceftazidime, imipenem, gentamicin, ciprofloxacin and trimethoprim-sulphamethoxazole, susceptible to piperacillin and amikacin, and had variable susceptibility to rifampicin and vancomycin. Two neonates were infected (one had pneumonia and one septicaemia and meningitis); the remaining six neonates were colonized in the respiratory secretions. Two cases occurred that could not be explained by cross-infection during the outbreak. Environmental screening recovered C. meningosepticum from sink taps. Pulsed-field gel electrophoresis of chromosomal macrorestriction digests of patient and environmental isolates showed them to be representatives of a single strain. The outbreak was controlled after staff were required to use an alcoholic handrub after washing hands, and toiletting of babies was done with sterile water instead of tap-water. Repair and chlorination of the water-tanks and changing the sink-taps resolves the outbreak.

Cross Infection↗
PubMed2001

Docetaxel-carboplatin as first line chemotherapy for epithelial ovarian cancer.

A prospective, non-randomized, multicentre, open, dose-finding study of a carboplatin-docetaxel (C-D) combination as first-line chemotherapy in FIGO stage Ic-IV epithelial ovarian cancer. C-D was given 3-weekly for 6 planned cycles, with a 3-day prophylactic dexamethasone regimen (8 mg b.i.d.). 139 eligible patients (Pts) (median age 56 years, range 28-85) were given a total of 750 cycles of chemotherapy in 5 cohorts: Co1, 32 pts, 169 cycles (C at AUC 5 + D 60 mg/m(2)); Co2, 22 pts, 122 cycles (5 + 75), Co3, 29 pts, 156 cycles (6 + 75), Co4, 27 pts, 146 cycles (7 + 75), Co5, 30 pts, 157 cycles (6 + 85). 110 patients (79%) completed 6 cycles; 17 (12%) stopped due to toxicity. 104 patients (75%) had CTC grade IV neutropenia, and 5 patients (4%) had this associated with fever. There were 2 probable treatment-related deaths. Only 8 patients (6%) experienced grade II-III neurotoxicity (all sensory; no motor > grade I). The maximum tolerated dose was reached in cohorts 4 and 5, and the dose limiting toxicities were myelosuppression and diarrhoea. The overall response rate for the study was 66% (49/74); CA125 response was 75% (70/93). Median progression-free survival was 16.6 months (95% CI 13.3-19.1). Recommended doses are carboplatin AUC 5 (via(51)Cr EDTA) or AUC 6 (if calculated) plus docetaxel 75 mg/m(2). A randomized trial comparing this regimen with carboplatin-paclitaxel has just completed recruitment.

Adenocarcinoma↗
PubMed2001

Survival of fecal coliforms in dry-composting toilets.

The dry-composting toilet, which uses neither water nor sewage infrastructure, is a practical solution in areas with inadequate sewage disposal and where water is limited. These systems are becoming increasingly popular and are promoted to sanitize human excreta and to recycle them into fertilizer for nonedible plants, yet there are few data on the safety of this technology. This study analyzed fecal coliform reduction in approximately 90 prefabricated, dry-composting toilets (Sistema Integral de Reciclamiento de Desechos Orgánicos [SIRDOs]) that were installed on the U.S.-Mexico border in Ciudad Juárez, Chihuahua, Mexico. The purpose of this study was to determine fecal coliform reduction over time and the most probable method of this reduction. Biosolid waste samples were collected and analyzed at approximately 3 and 6 months and were classified based on U.S. Environmental Protection Agency standards. Results showed that class A compost (high grade) was present in only 35.8% of SIRDOs after 6 months. The primary mechanism for fecal coliform reduction was found to be desiccation rather than biodegradation. There was a significant correlation (P = 0.008) between classification rating and percent moisture categories of the biosolid samples: drier samples had a greater proportion of class A samples. Solar exposure was critical for maximal class A biosolid end products (P = 0.001). This study only addressed fecal coliforms as an indicator organism, and further research is necessary to determine the safety of composting toilets with respect to other pathogenic microorganisms, some of which are more resistant to desiccation.

Bacteriological Techniques↗
PubMed2001

Policing and the mentally disordered.

I hope this article has given at least a flavour of the variety and complexity of challenges faced at the immediate operational level by police officers who have very little training in recognising the signs or symptoms of mental disorder and who very often have to deal with violent or irrational people who are quite simply criminal rather than ill. There is no question that in Dumfries Division police officers rely heavily upon the personal imput of on-call police doctors. Whilst at an operational level it is believed that incidents involvidng people with mental disorders are on the increase, it is particularly difficult to quantify exact extent of this perceived increase or indeed the impact which increasing abuse of alcohol and cotrolled drugs is having on the perception of mentally disordered offenders in the community. The vast majority of prisoners who are arrested and held within cells at Dumfries Police Office are suffering from some form of drug dependency and are in need of some form of assistance. Many display a variety of irrational behaviours when suffering the effects of drug withdrawal and increasingly it is difficult to keep any prisoner within the cells at Dumfries unless they have been examined by the on call police surgeon. Many are depressed, confused and increasingly providing at least verbal indicators that they are suicidal. It is more often the case that prisoners who are held within cells at Dumfries are in some form of constant observation whilst in our care. Given the increasing presence of mentally vulnerable people within our communities, it is vital that operational police officers play their part in responding appropriately to the needs of these people and the dangers they may pose to themselves or others. Dealing sensitively with increasing public concerns through appropriate community representative channels will also pose a considerable challenge. A challenge which can only be met through increasing awareness of the real situation and a commitment to enhance relationships across the caring and policing professions. The best chance of success in this area undoubtedly lies in the strength of these local relaitonships as progressed through honest and open inter-agency working.

Commitment of Persons with Psychiatric Disorders↗
PubMed2001

Cardiac troponin T predicts long-term outcomes in hemodialysis patients.

BACKGROUND: Increased plasma troponin T (cTnT), but not troponin I (cTnI), is frequently observed in end-stage renal failure patients. Although generally considered spurious, we previously reported an associated increased mortality at 12 months. METHODS: We studied long-term outcomes in 244 patients on chronic hemodialysis for up to 34 months, correlating the outcomes to plasma cTnT in routine predialysis samples. In addition, subsequent plasma samples at least 1 year later and within 6 months of data analysis were available in 97 patients and were used to identify patients with increasing plasma cTnT. The endpoints used were death and new or worsening coronary, cerebro-, and peripheral vascular disease and neuropathy. RESULTS: Transplantation occurred more frequently in patients with low initial cTnT: 31%, 13%, and 3% in the groups with cTnT < 0.010, 0.010-0.099, and > or = 0.100 microg/L, respectively. In the same groups, total deaths occurred in 6%, 43%, and 59% and cardiac deaths in 0%, 14%, and 24% of patients. In patients with follow-up samples, the group with increasing cTnT had a significantly increased death (relative risk, 2.0; P = 0.028). The increase was mainly in cardiac and sudden deaths. CONCLUSIONS: Higher plasma cTnT predicts long-term all-cause mortality in hemodialysis patients, even at concentrations < 0.100 microg/L, as does an increasing cTnT concentration over time.

Aged↗