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Biomedical subjects

A Wilson

Publications and source records attributed to A Wilson.

At least 199 records · Page 11Linked to original sources
PubMed1996

Influence of training dose on nicotine discrimination in humans.

Non-human research indicates that drug discrimination results may depend largely on the specific training conditions, including initial training dose. It has recently been shown that humans can discriminate among different doses of nicotine delivered by nasal spray. In this study, we examined the influence of training dose on subsequent behavioral discrimination of a range of nicotine doses. Male (n = 17) and female smokers (n = 16) were randomly assigned to "low" (10 micrograms/kg) versus "high" (30 micrograms/kg) nicotine training dose groups and trained reliably to discriminate this dose from placebo (0) on day 1 (> or = 80% correct identification). All but six subjects (four in low, two in high) learned this discrimination and continued on to day 2, in which both groups received 0, 5, 10, 20, and 30 micrograms/kg in ascending order (30 min between dosings) and were tested for generalization with their training dose using quantal and quantitative behavioral discrimination tasks. Subjective responses via traditional self-report measures were also assessed. Nicotine-appropriate responding on day 2 was significantly greater in low- versus high-dose groups, especially at 5 micrograms/kg. However, this difference due to training dose was seen more in women than in men. Discrimination behavior was associated with subjective effects of head rush in males, and with head rush and decline in urge to smoke in females. These results show that discriminative stimulus effects of nicotine are not fixed properties of the drug, but can be influenced by training conditions, and that effects associated with this discrimination may differ between men and women.

Adult↗
PubMed1996

Sequence analysis of wheat and oat furovirus capsid protein genes suggests that oat golden stripe virus is a strain of soil-borne wheat mosaic virus.

In northern blots, cDNA probes prepared to soil-borne wheat mosaic virus (SBWMV) RNA-1 and RNA-2 hybridized to RNA-1 and RNA-2, respectively, from a UK isolate of oat golden stripe virus (OGSV), as well as to their homologous RNAs. RT-PCR was used to amplify, clone and sequence a region of about 750 nucleotides spanning the capsid protein gene and part of the readthrough protein on RNA-2 from OGSV, a French isolate of SBWMV and two stable deletion mutants (Lab1 and Okl-7) of SBWMV isolates from Nebraska and Oklahoma respectively. There was very high (96.7-99.1%) nucleotide homology between all these sequences and the wild-type SBWMV sequences from Nebraska and Oklahoma. OGSV was more similar to SBWMV from France and Nebraska than were any of the isolates to SBWMV from Oklahoma. Of the few differences in the deduced amino acid sequences of the capsid proteins from the different isolates, OGSV differed from all SBWMV isolates only in one amino acid (isoleucine for valine at position 88). The high degree of similarity suggests that OGSV may best be classified as an oat strain of SBWMV.

Avena↗
PubMed1996

The effect of a rigid collar on intracranial pressure.

Spinal immobilization and the application of a rigid collar to protect the neck forms an integral part of care of the injured. The very nature of collar design predisposes to vascular obstruction of blood draining from the brain and theoretically may raise intracranial pressure (ICP). We analysed this effect prospectively in a series of injured patients using the Stifneck rigid collar, the most popular collar used in the UK. Comparison of the ICP before, during and after collar application showed a significant rise (P < 0.001), a mean rise in ICP of 4.5 mmHg, with a standard deviation of 4.1 mmHg. Insignificant changes in mean arterial pressure suggested that this effect is a response to distortion of venous drainage rather than cutaneous stimulation alone. Since head-injured patients with lowered level of consciousness form a key group who require cervical spinal immobilization it is essential that secondary insults producing raised ICP are minimized. Alternative forms of cervical spinal immobilization should be considered if collars impede venous drainage through the neck.

Catheterization, Central Venous↗
PubMed1996

The role of the periodontal ligament in bone modeling: the initial development of a time-dependent finite element model.

Current remodeling theories, as applied to long bones, suggest that such processes are controlled by mechanical strains either within or on the bone surface. In this study, the stresses and strains within the periodontal ligament and surrounding bone, consequent to orthodontic loading of a tooth, were investigated by application of the finite element method. Previously, various authors have applied two and three dimensional instantaneous (essentially static) models to analyze the problems. The study reported in this article describes an initial time-dependent (continuous/dynamic) finite element model for tooth movement that uses newly developed software, the results being cross-referenced against historical data. These early results, from a two-dimensional mathematical model of a loaded canine tooth, suggest that the remodeling process may be controlled by the periodontal ligament rather than the bone. In the finite element model, bone was found to experience a low strain of 1 x 10(-5), whereas the periodontal ligament experienced a strain of 0.1 when the "tooth model" is loaded. Only this latter figure is above the threshold usually reported to be necessary to initiate the remodeling process. Further developments in this rapidly advancing area of biomechanical research should facilitate a greater increase in our knowledge of tissue stress and strain after loading.

Bone Remodeling↗
PubMed1996

T cell receptor delta gene rearrangement and T early alpha (TEA) expression in immature alpha beta lineage thymocytes: implications for alpha beta/gamma delta lineage commitment.

Mature T cells comprise two mutually exclusive lineages expressing heterodimeric alpha beta or gamma delta antigen receptors. During development, beta, gamma, and delta genes rearrange before alpha, and mature gamma delta cells arise in the thymus prior to alpha beta cells. The mechanism underlying commitment of immature T cells to the alpha beta or gamma delta lineage is controversial. Since the delta locus is located within the alpha locus, rearrangement of alpha genes leads to deletion of delta. We have examined the rearrangement status of the delta locus immediately prior to alpha rearrangement. We find that many thymic precursors of alpha beta cells undergo VDJ delta rearrangements. Furthermore, the same cells frequently coexpress sterile T early alpha (TEA) transcripts originating 3' of C delta and 5' of the most upstream J alpha, thus implying that individual alpha beta lineage cells undergo sequential VDJ delta and VJ alpha rearrangements. Finally, VDJ delta rearrangements in immature alpha beta cells appear to be random, supporting models in which alpha beta lineage commitment is determined independently of the rearrangement status at the TCR delta locus.

Amino Acid Transport Systems, Basic↗
PubMed1996

Helicobacter pylori gastritis and serum pepsinogen levels in a healthy population: development of a biomarker strategy for gastric atrophy in high risk groups.

This study aimed to estimate the prevalence and type of chronic gastritis in an asymptomatic working population and to determine whether a combination of serum pepsinogen levels and Helicobacter pylori serology could be used to identify a subgroup with atrophic gastritis at elevated risk of gastric carcinoma. A 10% subsample of 544 male volunteer factory workers aged 18-63 years and participating in a larger study underwent endoscopy and biopsy. Of these men, 29 were seropositive for Helicobacter pylori; all but three (89.7%) had chronic gastritis. Serum pepsinogen A levels increased with progression from a corpus predominant pattern of gastritis through pangastritis to an antral predominant pattern. Nine subjects had corpus atrophy, which was in most cases accompanied by fasting hypochlorhydria and hypergastrinaemia. A combination of pepsinogen A below 80 ng ml-1 and Helicobaceter pylori seropositivity detected corpus atrophy with sensitivity 88.9% and specificity 92.3%. A second screening stage, using a pepsinogen A/C ratio of below 2.5 as a cut-off, resulted in a reduction in numbers requiring further investigation but with some loss of sensitivity (77.8%). Application of this two-stage screening programme to the original sample of 544 workers would have resulted in 11 (2.2%) men being selected for follow-up, excluding 25 (5.1%) false negatives. Our results suggest that a combination of serum pepsinogen levels and Helicobacter pylori serology could be useful as a biomarker strategy for detection of individuals at increased risk of gastric carcinoma and for non-invasive investigation of the natural history of Helicobacter pylori gastritis.

Adolescent↗
PubMed1996

Arabidopsis mutants showing an altered response to vernalization.

Flowering in many plant species is accelerated by a long period of cold temperature, known as a vernalization period. This research investigates how this cold temperature signal is perceived by plant cells and the mechanism by which it influences the transition to flowering. Mutagenesis of the late-flowering, vernalization-responsive, Arabidopsis mutant, fca, has yielded five independent mutations (termed vrn mutations) conferring an altered vernalization response. Allelism tests showed that these mutations fall into at least three complementation groups defining three loci named VRN 1, 2 and 3. The vrn1 and vrn2 mutations did not affect the acclimation response as judged by expression of cold-induced transcripts and freezing tolerance assays. vrn1-1 affected the short-day vernalization response of Landsberg erecta and reduced the vernalization response of other late-flowering Arabidopsis mutants. The acceleration of flowering by GA3 was not affected by vrn1-1. The VRN 1 locus was mapped to chromosome 3.

Acclimatization↗
PubMed1996

Use of a photoessay to teach low-income African American women about mammography.

BACKGROUND: Although incidence rates of breast cancer are lower among African American women than white women, mortality rates among African American women are higher, especially for women of lower socioeconomic levels. Reasons for this situation include the lesser use of breast cancer screening examinations by low-income, primarily African American women, late stage of diagnosis, and delays in treatment. METHODS: As part of community outreach and public health clinic inreach programs for the Forsyth County Cancer Screening Project, approximately 908 African American women who reside in low-income housing communities were targeted for educational efforts related to breast cancer screening. Early in the project, it was discovered that many of the women were unfamiliar with mammography and had very little awareness of how the entire examination was conducted. This low level of knowledge was particularly important because it was a barrier for obtaining regular mammography. A photoessay depicting the process of getting a mammogram was developed and used in community outreach efforts in three formats: in educational classes, as a display in the housing communities, and in physicians' offices. The acceptability of this photoessay to communicate knowledge of and reduce fears about mammography was assessed through evaluation surveys in interviews with a sample of 47 women from the target population. RESULTS: Overall, these women liked the photoessay and felt that it provided knowledge about mammography and reduced fears associated with anticipating mammography. CONCLUSIONS: Strategies such as this may be ideal to communicate important information about cancer prevention and control in low-literacy populations.

Adult↗
PubMed1996

Sampling for qualitative research using quantitative methods. 1. Measuring GPs' attitudes towards discussing smoking with patients.

BACKGROUND: Interview studies which employ qualitative methodology are often concerned with classifying behaviours or attitudes and an ideal sample of research subjects displays variety in the attitudes or behaviours under scrutiny. OBJECTIVE: This paper describes the development of a questionnaire which measures GPs' attitudes towards discussing smoking with patients with the intention of using this instrument to select GPs with diverse views for a qualitative interview study. METHOD: Thirteen attitude statements with an accompanying Likert-type scale were completed by 327 GPs in one FHSA area. Factor analysis of responses produced two subscales: 'perceived efficacy' and 'enthusiasm'. Reliability and validity of these were examined. RESULTS: Each subscale had good internal reliability and preliminary exploration of construct validity supported the notion that the subscales were valid. CONCLUSION: The use of this type of instrument in sampling GPs for qualitative studies could be effective for selecting subjects with a diversity of views towards the research topic.

Attitude of Health Personnel↗
PubMed1996

Saturation multipoint linkage mapping of chromosome 6q in type 1 diabetes.

Linkage analysis of type 1 diabetes sib pair families (n = 334) has suggested two separate regions of human chromosome 6q are linked to disease (designated IDDM5 and IDDM8). To test if these are false positive results, all available sib pair families (n = 429) were typed using a 92% informative map of chromosome 6q and multipoint analysis. The two regions still showed positive evidence of linkage, most notably the proterminal region, 6q27, corresponding to IDDM8 (MLS = 2.57, p = 0.0006; lambda s = 1.17). In addition, some evidence of transmission disequilibrium was seen with marker a046xa9 (IDDM5).

Chromosome Mapping↗
PubMed1996

Memory TCR repertoires analyzed long-term reflect those selected during the primary response.

Normal T cell repertoire selection and evolution in antigen-specific responses is poorly understood. We have recently described an MHC class I-restricted response characterized by an overwhelming expansion of CD8 cells expressing a Vbeta10 TCR, thus allowing the identification of antigen-selected cells directly ex vivo. Our present strategy to follow the overall TCR repertoire selection was to monitor the expression of a particular TCR alpha chain (Valpha8) on antigen-selected Vbeta10(+) cells by four-color flow cytometry. We demonstrate that while there is substantial variation among the responder mice in Valpha8 usage, the repertoires of individual animals remain relatively stable over long periods of time (>1 year), with or without repeated antigenic challenge. Thus if any evolution of this response occurs upon re-exposure to antigen, it would appear not to skew the TCR repertoire established during the primary response.

Animals↗
PubMed1996

Practical public health in a primary care setting. Discrete projects confer discrete benefits but a long-term relationship is needed.

Investigates a mechanism for delivering public health advice in a primary care setting--three West Yorkshire general practices--by seconding a public health physician (PHP) to each practice for six months, each practice receiving one day per week. Describes how the topics to be addressed--developing a practice plan for managing information; improving services available for Asian patients; and exploring "value for money" in fundholding--were chosen. Details the procedures and lists the main outcomes. Concludes that placing a public health physician in practices may not be the optimal approach for transferring public health knowledge, but topics important to the practice lend themselves to such an intervention, with potential long-term benefit for public health and primary care.

Family Practice↗
PubMed1996

Ethnicity and aged care assessment teams in Queensland.

To examine how functional, medical and psychosocial factors influence the differences in use of community and residential services by Australian-born and ethnic aged persons, all persons (n = 31,737) assessed by aged care assessment teams in Queensland in 1992 and 1993 were surveyed. Subjects were classified as Australian-born, overseas-born in countries where English is the primary language, or overseas-born in countries where English is not the primary language. Factors compared included use of services and residential care both prior to assessment and following assessment, and functional, medical and psychosocial factors. The group with non-English-speaking background were more likely to be both younger and underreferred compared to their proportion in the community. They were more likely to be referred for, and more likely to be recommended for, nursing home placement than the English-speaking groups. They were more commonly referred for assessment because of mental deficit problems, carer stress and/or social isolation, more likely to be diagnosed with dementia and diabetes, and less likely to be diagnosed with respiratory disease and vision disorders. That clients of non-English-speaking background are more likely to be recommended for nursing home placement is probably largely because of more advanced disease at the time of referral and therefore more functional dependence. Aged care assessment teams should increase ethnic communities' awareness of their services, particularly of the benefits of earlier referral.

Activities of Daily Living↗
PubMed1996

High levels of dopamine D2 receptor occupancy with low-dose haloperidol treatment: a PET study.

OBJECTIVE: The purpose of this study was to determine the dopamine D2 receptor occupancy induced by low-dose haloperidol treatment in a prospective trial. METHOD: Seven patients with schizophrenia were treated with 2 mg/day of haloperidol for 2 weeks, and D2 receptor occupancy was measured by [11C]raclopride and positron emission tomography. RESULTS: The patients showed high levels of D2 occupancy (53%-74%); five of them showed substantial clinical improvement, and none showed important side effects. CONCLUSIONS: The findings demonstrate that low doses of haloperidol induce D2 receptor occupancies that are in the putative therapeutic range. In combination with recent empirical trials, these findings should encourage clinicians to initiate treatment of psychotic episodes with low (2-4 mg haloperidol equivalent) doses of typical neuroleptics, particularly for first-episode patients.

Adult↗
PubMed1996

The transference and the zone of proximal development.

The Zone of Proximal Development (ZPD) is discussed, a construct that, when introduced into psychoanalysis, advances understanding of the key clinical relationship between the intrapsychic and the interpersonal. Strands from several psychoanalytic formulations are brought together and forged into a coherent construct, which is then contrasted with the transference. It is shown how the ZPD provides the transference with its mutative potential. Just as the transference provides the motivation for the recruitment of objects to accomplish its purposes (repetition), the ZPD leads to the recruitment of objects in order to accomplish its purposes (to learn by ushering individuals into a speech and internalization community). Under the sway of the transference objects are sought so that early disregulating experiences can be repeated and an opportunity provided for a better resolution. The ZPD works in tandem with the transference, capitalizing on the impetus provided, allowing for the possibility of internalization, a beneficial outcome to transference repetition which otherwise would have no agent of conflict resolution. In analysis, when the transference and the ZPD enjoin smoothly, the potential outcome is "insight" in a broad sense. The processes of the ZPD define the optimal interpersonal context of psychoanalysis, one that allows the intrapsychic to be best reached by analytic interventions. Given the inevitability of mutual influences between analyst and analysand, the analyst strives simultaneously to be in the ZPD yet outside the transference with the analysand, a crucial tension that is a constant, precarious technical factor. This useful tension casts light on such procedural guides as optimal frustration and abstinence.

Humans↗