PubMed Health⌕ Search

Biomedical subjects

R Henson

Publications and source records attributed to R Henson.

18 recordsLinked to original sources
PubMed2000

Neuroimaging evidence for dissociable forms of repetition priming.

Repetition priming has been characterized neurophysiologically as a decreased response following stimulus repetition. The present study used event-related functional magnetic resonance imaging to investigate whether this repetition-related response is sensitive to stimulus familiarity. A right fusiform region exhibited an attenuated response to the repetition of familiar stimuli, both faces and symbols, but exhibited an enhanced response to the repetition of unfamiliar stimuli. Moreover, both repetition effects were modulated by lag between successive presentations. Further experiments replicated the interactions between repetition, familiarity, and lag and demonstrated the persistence of these effects over multiple repetitions. Priming-related responses are therefore not unitary but depend on the presence or absence of preexisting stimulus representations.

Adult↗
PubMed2000

Mass screening in low-income populations: the challenges of securing diagnostic and treatment services in a national cancer screening program.

Funding for many mass screening programs for low-income and uninsured populations provides resources for screening tests, yet only rarely does it provide coverage for necessary follow-up diagnostic and treatment services. The National Breast and Cervical Cancer Early Detection Program (NBCCEDP), a federally funded initiative that provides cancer screening to low-income uninsured and underinsured women, covers some diagnostic follow-up tests and no treatment services. We conducted in-depth case studies of seven state programs participating in the NBCCEDP to investigate the strategies and approaches being used to secure diagnostic and treatment services. The results suggest that the program relies on a patchwork of resources--at state and local levels--to provide diagnostic and treatment services. This includes a number of components of local safety nets, all of which are unstable and have uncertain futures. Public health disease-screening initiatives need to reconsider the feasibility of continued reliance on case-by-case appeals to the local safety net for diagnostic follow-up and treatment services.

Breast Neoplasms↗
PubMed1999

Injury control strategies: extending the quality and quantity of data relating to road traffic accidents in children.

This review describes how an extended database of information can provide the opportunity to go beyond the traditionally distinct health, engineering, and education initiatives in order to identify the effectiveness of more overarching policies for injury control. Such information can be used to raise awareness and to encourage community participation in designing a road traffic accident prevention strategy.

Accidents, Traffic↗
PubMed1998

Cervical cancer screening among low-income women: results of a national screening program, 1991-1995.

OBJECTIVE: To evaluate the results of cervical cytology screening in the National Breast and Cervical Cancer Early Detection Program and to compare the findings with results from other screening programs. METHODS: We analyzed data on 312,858 women aged 18 years and older who received one or more Papanicolaou smears, and follow-up if indicated, from October 1991 through June 1995 at screening sites across the United States providing comprehensive National Breast and Cervical Cancer Early Detection Program services. RESULTS: Of the women screened, more than half were 40 years or older; slightly less than half (44%) were of racial and ethnic minorities. During the first screening cycle, 3.8% of Papanicolaou tests were reported as abnormal (squamous intraepithelial lesion [SIL] or squamous cell cancer); proportions of abnormals decreased with increasing age. The age-adjusted rate of biopsy-confirmed cervical intraepithelial neoplasia (CIN) II or worse among women screened was 7.4 per 1000 Papanicolaou tests; rates of CIN were highest among young women, but cancer rates peaked among women in their 50s and 60s. The percentages of first screening cycle-Papanicolaou tests interpreted as high-grade SIL and squamous cell carcinoma associated with biopsy-confirmed CIN II or worse (the positive predictive value) were 56.0% for CIN II/III and 3.7% for invasive cancer. Of the 150 invasive cancers diagnosed, 54.0% were classified as local disease. CONCLUSION: Observed results emphasize the duality of cervical neoplasia-CIN in younger women and invasive cancer in older women. This finding points to the importance of reaching both younger and older women for cervical cancer screening.

Adult↗
PubMed1996

Working memory in chess.

Three experiments investigated the role of working memory in various aspects of thinking in chess. Experiment 1 examined the immediate memory for briefly presented chess positions from master games in players from a wide range of abilities, following the imposition of various secondary tasks designed to block separate components of working memory. Suppression of the articulatory loop (by preventing subvocal rehearsal) had no effect on measures of recall, whereas blocking the visuospatial sketchpad (by manipulation of a keypad) and blocking the central executive (by random letter generation) had equivalent disruptive effects, in comparison with a control condition. Experiment 2 investigated the effects of similar secondary tasks on the solution (i.e., move selection) of tactical chess positions, and a similar pattern was found, except that blocking the central executive was much more disruptive than in Experiment 1. Experiment 3 compared performance on two types of primary task, one concerned with solving chess positions as in Experiment 2, and the other a sentence-rearrangement task. The secondary tasks in each case were both designed to block the central executive, but one was verbal (vocal generation of random numbers), while the other was spatial in nature (random generation of keypresses). Performance of the spatial secondary task was affected to a greater extent by the chess primary task than by the verbal primary task, whereas there were no differential effects on these secondary tasks by the verbal primary task. In none of the three experiments were there any differential effects between weak and strong players. These results are interpreted in the context of the working-memory model and previous theories of the nature of cognition in chess.

Adult↗
PubMed1993

An analysis of job morale factors of community health nurses who report a low turnover rate. The research.

Nurse executives are continually faced with issues related to nursing turnover and staff morale. This sample included 217 registered nurses working in a state health department where the turnover rate was 8%. In this study, the authors found that nurses with advanced educational preparation, higher-level positions, or both, demonstrated increased levels of morale. Conversely, nurses with increased years of service and nursing experience had lower morale levels. These findings could be useful in delineating situations to improve morale and lower turnover rates.

Adult↗
PubMed1986

Compliance with anticonvulsant therapy by epileptic youth. Relationships to psychosocial aspects of adolescent development.

Independence in daily life, family harmony as perceived by youths and their parents, and self-esteem were investigated in relation to anticonvulsant medication compliance in 25 epileptics aged 9-17 years. Medication compliance was assessed by monthly home saliva sampling for phenobarbital concentrations. Psychosocial issues were assessed by standardized instruments. Each psychosocial issue was highly correlated with compliance. Partial correlation analysis reveals that these findings are not explained by the subject's demographic or clinical characteristics. Medication noncompliance appears to be associated with a restriction of independence in daily life, lack of harmony in family relations, and low self-esteem in teenage epileptics. Clinicians should observe for these conditions and initiate patient and family counseling in order to maximize medication compliance and seizure control.

Adolescent↗
PubMed1981

Pharmacokinetics of intravenous and oral tolmesoxide.

A high pressure liquid chromatographic assay was developed for simultaneous measurement of the plasma levels of tolmesoxide and its principal metabolite, RX71112. The assay was used to study the disposition of intravenous and oral tolmesoxide in ten normotensive subjects. Two exponential terms were required to describe the disposition of the drug following intravenous administration, whilst a single exponential term sufficed to account for the decay in the plasma concentration after oral administration. The bioavailability of oral tolmesoxide from capsules averaged 84.5% and was independent of dose. The mean half-life after i.v. dosing was 2.6 h (+/- 0.3 SEM) compared to values of 1.9 h (+/- 0.1 SEM) and 2.7 h (+/- 0.5 SEM) following 200 and 400 mg oral doses respectively. In all subjects RX71112 appeared in plasma shortly after tolmesoxide following both routes of administration. The terminal half-life of the metabolite was significantly longer than tolmesoxide with a mean value of 4.9 h (+/- 0.9 SEM) following the 200 mg oral dose of tolmesoxide. The binding of tolmesoxide and RX71112 at therapeutic plasma concentration was 36.8% (+/- 0.5 SEM) and 58.5% (+/- 0.3 SEM) and this remained unchanged at higher concentrations.

Administration, Oral↗
PubMed1980

Pharmacokinetics of fenclofenac following single and multiple doses.

The plasma concentration of the anti-inflammatory drug fenclofenac was investigated in volunteers following single oral doses of 200, 500 and 600 mg, as well as multiple doses of 600mg b.i.d. over five days, using gas chromatography with electron capture detection. The pharmacokinetic parameters derived were independent of dose, and the terminal half-life, t1/2, varied independently of dose between 20 and 38 hours (27.23 +/- 1.8 at 600mg). The apparent volume of distribution (Vd area) had similar values at doses of 200, 500 and 600mg of 15.2 +/- 2.6, 18.2 +/- 1.5 and 14.7 +/- 1.7 litres respectively. These small volumes of distribution indicate that fenclofenac distributes mainly into extracellular space. A mean peak plasma concentration of 63.5 +/- 4.6microgram/ml developed after 3 to4 hours following a single 600mg dose whilst a mean steady state plasma concentration (600mg b.i.d.) of 86.9 +/- 5.7 microgram/ml was achieved within four days, and this decayed with a mean terminal half-life of 25.9 +/- 4.2 hours.

Adult↗
PubMed1980

Plasma concentration and disposition of buprenorphine after intravenous and intramuscular doses to baboons.

Buprenorphine is a newly-developed strong analgesic. A selected ion monitoring method has been developed to measure its plasma levels over the concentration range 20-3000ng ml-1. Six baboons each received intravenous and intramuscular doses of buprenorphine hydrochloride at a level of 5mg/kg in a cross-over study. The mean peak plasma concentrations (+/-standard deviation) were 2290 +/- 357ng ml-1 and 805 +/- 416ng ml-1 respectively and the corresponding times to the peak levels were 4.0 +/- 1.5 minutes and 30.3 +/- 24.6 minutes suggesting the rapid release of the drug from intramuscular sites. Comparison of areas under the plasma concentration versus time curves to 24 hours after dosing showed the mean bioavailability of buprenorphine from the intramuscular doses was 70% of that from the reference intravenous doses.

Animals↗
PubMed1980

Waldenström's macroglobulinemia and autoimmune disease in a family.

We diagnosed Waldenström's macroglobulinemia in a father and three offspring. Clinical and subclinical autoimmune disorders occurred excessively in the family. The HLA haplotype A2, B8, DRw3 was detected in all patients with Waldenström's macroglobulinemia and all but one family member with autoimmune manifestations. A lod score [log odds] of 4.86 favors linkage to the HLA complex of a gene predisposing to lymphoproliferative and autoimmune disorders. Associated with this HLA haplotype were the B-cell alloantigens Ia-172 and 350, previously reported in patients with the lymphoma-prone sicca syndrome.

Adult↗
PubMed1979

Properties of cupric ions in benzylamine oxidase from pig plasma as studied by magnetic-resonance and kinetic methods.

Benzylamine oxidase from pig plasma has been studied by a variety of chemical and physical techniques. 1. Analytical ultracentrifugation, gel electrophoresis and isoelectric-focusing studies suggest that the enzyme is composed of two subunits with closely similar primary structures. 2. E.s.r. and n.m.r. measurements show that the enzyme contains two well-separated (greater than 0.6 nm) Cu2+ ions at chemically distinct sites. Each Cu2+ ion is coordinated by two water molecules, one 'axial' and the other 'equatorial'. Both water molecules undergo fast exchange (10(5)--10(8) s-1) with solvent and are deprotonated in the pH range 8--9, but only the equatorial water molecule is displaced by the inhibitors N3- and CN-. 3. Kinetic and e.s.r. measurements show that azide and cyanide compete against O2 binding and also make the two Cu2+ sites identical. It is concluded that Cu2+ must participate in the re-oxidation of reduced enzyme by molecular O2.

Animals↗