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Biomedical subjects

A Wilson

Publications and source records attributed to A Wilson.

At least 181 records · Page 10Linked to original sources
PubMed1997

Adolescent suicidality in urban minorities and its relationship to conduct disorders, depression, and separation anxiety.

OBJECTIVE: This research investigates personality variables--aggression and disorders of conduct, depression, and separation anxiety--mediating suicidal behavior in psychiatrically hospitalized urban minority adolescents. METHOD: Four matched groups of 26 subjects (N = 104) participated: suicidal adolescents with, and suicidal adolescents without, a conduct disorder diagnosis, nonsuicidal adolescents with a conduct disorder diagnosis, and a nonpsychiatric control group. Subjects were assessed with three dimensions from the Epigenetic Assessment Rating System (EARS), the Children's Depression Inventory (CDI), and the Separation Anxiety Test (SAT). RESULTS: A conduct disorder diagnosis was related to lower modal EARS scores. The EARS and the CDI each identified a different subset of suicidal adolescents. Adolescents with lower modal EARS scores exhibited greater reactivity to separation experiences on the SAT. CONCLUSION: Relying on depressive symptomatology to identify suicidality overlooks a majority of at-risk adolescents. Structural personality variables as measured by the EARS identify and distinguish subsets of suicidal adolescents.

Adolescent↗
PubMed1997

ADHD and FAS.

Explore the source record for details and available documents.

Attention Deficit Disorder with Hyperactivity↗
PubMed1997

Reliability of a simple non-invasive method for the evaluation of 5-HT2 receptors using [18F]-setoperone PET imaging.

Position emission tomography (PET) imaging of 5-HT2 receptors can be potentially very useful in investigating neuropsychiatric disorders and their pharmacological treatments. [18F]-setoperone, a PET radio-ligand, has been shown to be useful for the delineation of 5-HT2 receptors in the cortex. However, there is no available data regarding the scan-rescan reliability of this technique. The purpose of this study was to assess the reliability of the [18F]-setoperone PET technique for assessing the binding potential (Bmax/ Kd) for 5-HT2 receptors. Ten healthy subjects had two [18F]-setoperone PET scans on two separate occasions 6-21 days apart. The average difference in the 5-HT2 binding potential (BP) as measured on the two occasions in the prefrontal, temporal, parietal and occipital region was between 5 and 7%. Thus 5-HT2 BP can be measured with a high reliability using a non-invasive technique that uses the cerebellum as a reference region. A power analysis based on the reliability data suggests that this technique can be used to detect within-subject differences of 10% or more, and between-group differences of 25% or more, with a reasonable number of subjects. It is concluded that [18F]-setoperone can be routinely produced and reliably used for the PET imaging of 5-HT2 receptors in clinical situations.

Adult↗
PubMed1997

Impact during equine locomotion: techniques for measurement and analysis.

Impact is implicated in the development of several types of musculoskeletal injury in the horse. Characterisation of impact experienced during strenuous exercise is an important first step towards understanding the mechanism for injury. Measurement and analysis of large, short duration impacts is difficult. The measurement system must be able to record transient peaks and high frequencies accurately. The analysis technique must be able to characterise the impact signal in time and frequency. This paper presents a measurement system and analysis technique for the characterisation of large impacts. A piezo-electric accelerometer was securely mounted on the dorsal surface of the horses hoof. Saddle mounted charge amplifiers and a 20 m coaxial cable transferred these data to a PC based logging system. Data were down-loaded onto a UNIX workstation and analysed using a proprietary statistics package. The values of parameters calculated from the time series data were comparable to those of other authors. A wavelet decomposition showed that the frequency profile of the signal changed with time. While most spectral energy was seen at impact, a significant amount of energy was contained in the signal immediately following impact. Over 99% of this energy was contained in frequencies less than 1250 Hz. The sampling rate and the frequency response of a measurement system for recording impact should be chosen carefully to prevent loss or corruption of data. Time scale analysis using a wavelet decomposition is a powerful technique which can be used to characterise impact data. The use of contour plots provides a highly visual representation of the time and frequency localisation of power during impact.

Acceleration↗
PubMed1997

Manic indices on the Rorschach.

This study examined signs of mania on the Rorschach, specifically whether manic inpatients (n = 24) produce different thematic content and thought disorder than comparison groups of paranoid schizophrenic (n = 27) and schizoaffective (n = 25) inpatients. Rorschach protocols were scored by a trained rater for the Thought Disorder Index and the Schizoid-Affective Rating Scale. Results indicated that all 3 groups had moderate levels of thought disorder, but the manic inpatients produced significantly more combinatory thinking and affective content responses than the other 2 groups. The paranoid schizophrenic and schizoaffective patients did not produce significantly more schizoid content and were not different on any other types of thought disorder than the manic patients. These findings are discussed in terms of the contribution of thought disorder and affective thematic content in making the diagnosis of mania on the Rorschach.

Adult↗
PubMed1997

[11C]RTI-32 PET studies of the dopamine transporter in early dopa-naive Parkinson's disease: implications for the symptomatic threshold.

To estimate the threshold of nigrostriatal dysfunction required for symptomatic Parkinson's disease (PD), we employed [11C]RTI-32 and PET to study the dopamine transporter in striatal subdivisions of 11 L-dopa-naive patients with very early parkinsonism. As compared with the controls (N = 10), the PD group had on the side contralateral to the maximal clinical symptoms, significantly reduced binding in the posterior putamen (-56%) and anterior putamen (-28%), with the reduction in caudate (-12%) not significantly different. To the extent that dopamine transporter binding accurately reflects the number of nigrostriatal dopamine nerve terminals, these findings suggest that the clinical threshold for PD in the middle-age human is approximately 50% loss of dopaminergic innervation to the posterior putamen. Our data also suggest that damage to the putamen component of the striatum is sufficient for the clinical expression of PD.

Adult↗
PubMed1997

The leg ulcer resource team: a standard of care.

A leg ulcer resource team was formed to introduce and implement a standard of care for patients with leg ulcers. An audit of the standard following implementation showed that 82% of ulcers had been classified correctly, diagnostic tools had been used in 78% of cases and a clear rationale for care given in 86%. However, accurate identification of patient needs in the care plan occurred in only 39% of cases, and only 60% of care plans had ulcer size and site recorded. Patient education was also a problem--25% of patients did not know what type of ulcer they had and only 43% could describe care of their ulcer or identify risk factors associated with leg ulceration.

Community Health Nursing↗
PubMed1997

From vision to reality--managing change in the provision of library and information services to nurses, midwives, health visitors and PAMs: (professions allied to medicine) a case study of the North Thames experience with the Inner London Consortium.

One of the North Thames' pioneering consortia, the Inner London Consortium (ILC) is a complex body which includes NHS Trusts with teaching hospital university connections, community-based Trusts and general hospital acute Trusts. Within the consortium there are 12,000 trained nurses, midwives, health visitors and other professional staff working in the professions allied to medicine (PAMs), all of whom require access to and provision of appropriate library information services. In 1994, taking into account experiences elsewhere in the Region and nationally, it became clear that library issues were complex and would become acute with the move of nursing libraries from ILC Trust sites over a very short timescale. A report on the issues commissioned by the Consortium recommended that a library project, which built on existing NHS Trust PGMDE funded library resources and moved these to a multidisciplinary base to serve the consortium membership, be implemented. The objective of providing access to library information services for nurses and PAMs was achieved. Successes that emerged from the implementation included: The registration in Trust libraries of almost 12 000 new members within the initial 6-month monitoring period. The development of service level agreements and standards for the delivery of services to these new user groups. This paper describes the processes behind these significant and complex changes.

Allied Health Personnel↗
PubMed1997

Repopulation of freeze-dried porcine valves with human fibroblasts and endothelial cells.

BACKGROUND AND AIMS OF THE STUDY: There is a need for a replacement cardiac valve constructed from non-immunogenic materials but incorporating living, and preferably autologous, cells. The object of this study was to colonize freeze-dried porcine valve leaflets with human fibroblasts and vascular endothelial cells. METHODS: Porcine pulmonary valve leaflets were freeze-dried to produce a porous matrix having communicating cavities of appropriate dimensions for fibroblast repopulation. Cultured human fibroblasts and vascular endothelial cells that had been cryopreserved by standard methods were added to freeze-dried leaflets. Following culture at 37 degrees C, the leaflets were examined by confocal scanning microscopy and transmission electron microscopy. RESULTS: Mechanical perforation of the leaflet surface permitted colonization of the freeze-dried matrix by fibroblasts; under the conditions we studied, the cell density did not reach physiologic levels but those cells that were present were well attached and metabolically active. Gentle cotton abrasion of the surface of the freeze-dried leaflets provided a suitable substrate for endothelial cell attachment and confluence was achieved in 10 days. Leaflets were perforated, cultured with human fibroblasts for 10 days, then gently rubbed with a cotton bud and cultured for a further 10 days with human endothelial cells. The endothelial cells formed a confluent layer on the surface and viable fibroblasts were present within the substance of the leaflet. CONCLUSION: Although these results are preliminary, they demonstrate the basic feasibility of this approach to the production of xenogeneic valves that contain the patient's own cells.

Animals↗
PubMed1996

Induction of activator protein (AP)-1 and nuclear factor-kappaB by CD28 stimulation involves both phosphatidylinositol 3-kinase and acidic sphingomyelinase signals.

A major obstacle in understanding the signaling events that follow CD28 receptor ligation arises from the fact that CD28 acts as a costimulus to TCR engagement, making it difficult to assess the relative contribution of CD28 signals as distinct from those of the TCR. To overcome this problem, we have exploited the observation that activated human T cell blasts can be stimulated via the CD28 surface molecule in the absence of antigenic challenge; thus, we have been able to observe the response of normal T cells to CD28 activation in isolation. Using this system, we observed that CD28 stimulation by B7-transfected CHO cells induced a proliferative response in T cells that was not accompanied by measurable IL-2 production. However, subsequent analysis of transcription factor generation revealed that B7 stimulation induced both activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB) complexes, but not NF-AT. In contrast, engagement of the TCR by class II MHC/superantigen, either with or without CD28 ligation, resulted in the induction of NF-AT, AP-1, and NF-kappaB as well as IL-2 production. Using selective inhibitors, we investigated the signaling pathways involved in the CD28-mediated induction of AP-1 and NF-kappaB. This revealed that NF-kappaB generation was sensitive to chloroquine, an inhibitor of acidic sphingomyelinase, but not to the phosphatidylinositol 3-kinase inhibitor, wortmannin. In contrast, AP-1 generation was inhibited by wortmannin and was also variably sensitive to chloroquine. These data suggest that in activated normal T cells, CD28-derived signals can stimulate proliferation at least in part via NF-kappaB and AP-1 generation, and that this response uses both acidic sphingomyelinase and phosphatidylinositol 3-kinase-linked pathways.

Animals↗
PubMed1996

Role of gamma delta T cells in pathogenesis and diagnosis of Behcet's disease.

BACKGROUND: Behcet's disease (BD) is a multisystem disorder of unknown pathogenesis. The diagnosis is based on a set of international clinical criteria. Previous investigations have suggested that immunological cross-reactivity between peptides within streptococcal heat-shock proteins and human peptides might be involved in the pathogenesis of BD. We tested four peptides from mycobacterial heat-shock proteins to see if they specifically stimulated gamma delta T cells from BD patients. We then investigated this response to see whether it could be used as a laboratory test to diagnose BD. METHODS: We used a T-cell proliferative test to assay responses to four mycobacterial 65 kDa heat-shock-protein peptides and to four homologous peptides derived from the sequence of the human 60 kDa heat-shock protein. FINDINGS: We elicited significant gamma delta T-cell responses to the mycobacterial peptides in 25 (76%) of 33 patients with BD, compared with 2 (3.6%) of 55 controls with recurrent oral ulcers, systemic disease, or no disorders. The proportion of BD patients who had false-negative results decreased if the test was done during clinical manifestation of disease activity. There was a correlation between disease activity and T-cell responses. Four homologous peptides from human 60 kDa heat-shock protein also specifically stimulated T cells from patients with BD but with lower stimulation indices. INTERPRETATION: Activation of peripheral-blood mononuclear cells with the four heat-shock-protein peptides elicited significant T-cell proliferative responses by the gamma delta subset of T cells, which may regulate alpha beta T cells. Because these peptides have a high specificity for BD, this assay can be used as a laboratory diagnostic test for BD.

Adult↗
PubMed1996

Regulation of P120 mRNA levels during lymphocyte stimulation: evidence that the P120 gene shares properties with early and late genes.

P120 is a growth-regulated nucleolar protein, the expression of which is required for G1- to S-phase transition in lymphocytes. P120 appears to be involved in ribosomal biogenesis presumptively through its putative role as a rRNA methyltransferase. To better understand the role of P120 in cell cycle progression, we examined the regulation of the P120 gene in resting lymphocytes and in mitogen-stimulated lymphocytes as they progress from G1-phase toward S-phase. P120 mRNA was detected after the immediate early gene c-fos and persisted as the cells approached S-phase. A decrease in P120 mRNA coincided with the expression of histone H3 mRNA. The level of P120 mRNA increased as cells proceeded through G1-phase, and this increase was attributed to a more than threefold increase in the P120 transcription rate and an increase in P120 mRNA stability. The P120 gene is transcribed in resting lymphocytes, although the steady-state level of P120 is small or nonexistent. P120 mRNA accumulates in resting cells in the presence of the protein synthesis inhibitor cycloheximide. Furthermore, the steady-state level of P120 mRNA increases in the presence of cycloheximide after PHA-stimulation; this level does not increase in cells not treated with this protein synthesis inhibitor. The presence of cycloheximide increases both the transcription rate of the P120 gene and the stability of P120 mRNA. These studies indicate that P120 expression is cell cycle regulated in a complex manner and that the P120 gene has properties of both early and late genes. This time ordered regulation for P120 expression may represent a necessary step for the cell cycle associated increase in ribosomal biogenesis that is required for G1-to S-phase transition.

Cell Cycle↗
PubMed1996

Selectively impaired development of intestinal T cell receptor gamma delta+ cells and liver CD4+ NK1+ T cell receptor alpha beta+ cells in T cell factor-1-deficient mice.

T cell factor-1 (Tcf-1) is a transcription factor that binds to a sequence motif present in several T cell-specific enhancer elements. In Tcf-1-deficient (Tcf-1-/-) mice, thymocyte development is partially blocked at the transition from the CD4-8+ immature single-positive stage to the CD4+8+ double-positive stage, resulting in a marked decrease of mature peripheral T cells in lymph node and spleen. We report here that the development of most intestinal TCR gamma delta+ cells and liver CD4+ NK1.1+TCR alpha beta+ (NK1+T) cells, which are believed to be of extrathymic origin, is selectively impaired in Tcf-1-/- mice. In contrast, thymic and thymus-derived (splenic) TCR gamma delta+ cells are present in normal numbers in Tcf-1-/- mice, as are other T cell subsets in intestine and liver. Collectively, our data suggest that Tcf-1 is differentially required for the development of some extrathymic T cell subsets, including intestinal TCR gamma delta+ cells and liver CD4+ NK1+T cells.

Animals↗