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Biomedical subjects

D Wallace

Publications and source records attributed to D Wallace.

At least 73 records · Page 4Linked to original sources
PubMed1998

An in vivo comparison between a visible light-cured bonding system and a chemically cured bonding system.

Direct bonding of brackets has become a routine procedure in clinical orthodontics. Many techniques and materials are currently advocated and used, the most recent being light-cured composites. Advantages of the light-cured systems are their relative ease of use, improved bracket placement, and more rapid set of the composite. For a new system to be clinically viable, it must possess properties that are at least as reliable as existing systems. The purpose of this longitudinal clinical study was to evaluate and compare the rate of success and/or failure between a visible light-cured bonding material (Sequence) and a chemically cured bonding material (System 1+), using both systems in every patient. Contralateral quadrants were bonded with each system respectively. A total of 32 patients were followed for a mean period of 11 months (range of 3 to 21 months), with a total of 531 brackets bonded, 265 with visible light-cured and 266 with chemically cured resins. Failures for each system were recorded and failure rates calculated. The failure rate of the visible light-cured composite was 11.3% and that of the chemically cured composite was 12%. A Chi-squared (chi2) test did not reveal any statistically significant differences between the failure rates of the two systems, (chi2 = 0.014, df-1, P > 0.9).

Acid Etching, Dental↗
PubMed1998

Acute intraoperative suprachoroidal haemorrhage in ocular surgery.

PURPOSE/BACKGROUND: Acute intraoperative suprachoroidal haemorrhage (AISH) is the most sight-threatening complication of ocular surgery. We investigated the visual outcomes following this intraoperative event, patient characteristics that may predispose to it and the clinical features that may be of prognostic significance. METHODS: The records of 45 cases of AISH collected from ophthalmic centres in the United Kingdom, Republic of Ireland and Switzerland were reviewed. Two satisfactory controls in terms of operative procedure, surgeon, age (+/- 5 years) and gender were found for each of 33 of our cases. Systemic and ocular characteristics were compared for cases and controls, and the visual results of all cases of AISH are analysed. RESULTS: Cases and controls differed only in terms of axial length and pre-operative intraocular pressure, both of which were significantly greater for eyes that experienced an AISH (p < 0.05). Ten eyes (22.2%) achieved a final Snellen acuity of 6/12 or better. Statistically significant associations with a final acuity of counting fingers or worse included spontaneous nuclear expression (p = 0.02), retinal detachment (p < 0.0001), four-quadrant suprachoroidal haemorrhage (p = 0.007) and vision of perception of light or worse at the first dressing (p = 0.0001). Four of the 6 eyes that experienced an AISH during phacoemulsification surgery had a visual outcome of 6/12 or better, and this was significantly greater than for cases involving extracapsular cataract surgery (p = 0.004). CONCLUSION: The results indicate that longer axial length and higher pre-operative intraocular pressure are associated with increased risk of AISH. Poor visual results are more likely following spontaneous nuclear expression, retinal detachment, four-quadrant suprachoroidal haemorrhage or vision of perception of light or worse at the first dressing. The results also suggest that AISH complicating a phacoemulsification procedure has a more favourable visual prognosis than AISH that occurs during extracapsular cataract surgery.

Acute Disease↗
PubMed1998

A randomized, controlled pilot study of a home-based exercise program for individuals with mild and moderate stroke.

BACKGROUND AND PURPOSE: Many stroke survivors have minimal to moderate neurological deficits but are physically deconditioned and have a high prevalence of cardiovascular problems; all of these are potentially modifiable with exercise. The purposes of this randomized, controlled pilot study were (1) to develop a home-based balance, strength, and endurance program; (2) to evaluate the ability to recruit and retain stroke subjects; and (3) to assess the effects of the interventions used. METHODS: Twenty minimally and moderately impaired stroke patients who had completed inpatient rehabilitation and who were 30 to 90 days after stroke onset were randomized to a control group or to an experimental group that received a therapist-supervised, 8-week, 3-times-per-week, home-based exercise program. The control group received usual care as prescribed by the patients' physicians. Baseline and postintervention assessments included the Fugl-Meyer Motor Assessment, the Barthel Index of Activities of Daily Living (ADL), the Lawton Scale of Instrumental ADL, and the Medical Outcomes Study-36 Health Status Measurement. Functional assessments of balance and gait included a 10-m walk, 6-Minute Walk, and the Berg Balance Scale. Upper extremity function was evaluated by the Jebsen Test of Hand Function. RESULTS: Of 22 patients who met study criteria, 20 completed the study and 2 refused to participate. The experimental group tended to improve more than the control group in motor function (Fugl-Meyer Upper Extremity: mean change in score, 8. 4 versus 2.2; Fugl-Meyer Lower Extremity: 4.7 versus -0.9; gait velocity: median change, 0.25 versus .09 m/s; 6-Minute Walk: 195 versus 114 ft; Berg Balance Score: 7.8 versus 5; and Medical Outcomes Study-36 Health Status Measurement of Physical Function: 15. 5 versus 9). There were no trends in differences in change scores by the Jebsen Test of Hand Function, Barthel Index, and Lawton Instrumental ADL Scale. CONCLUSIONS: This study demonstrated that a randomized, controlled clinical trial of a poststroke exercise program is feasible. Measures of neurological impairments and lower extremity function showed the most benefit. Effects of the intervention on upper extremity dexterity and functional health status were equivocal. The lasting effects of the intervention were not assessed.

Activities of Daily Living↗
PubMed1998

Scales of geography, time, and population: the study of violence as a public health problem.

OBJECTIVES: In this study, data on violent deaths in the Bronx, New York City, from the 1970, 1980, and 1990 censuses were analyzed. METHODS: The incidence and areal density of intentional deaths were mapped by health area. Simple and stepwise regressions between violent death measures and other factors were performed. RESULTS: The incidence of deaths at levels of those in the highest 1970 quintile spread so that by 1990 only 2 areas saw incidences at levels of the lowest 1970 quintile. Overcrowding, socioeconomic status, population, population change, and drug deaths in simple regressions and overcrowding, socioeconomic status, and low-weight births in stepwise regressions correlated significantly with violent death incidence or density. CONCLUSIONS: Understanding the spatiotemporal development of violence can contribute to public policy on violence.

Censuses↗
PubMed1998

Determinants of self-efficacy among persons with spinal cord injuries.

The purpose of this study was to determine the factors affecting self-efficacy among persons with spinal cord injury (SCI). The study population consisted of 105 persons with SCI who were discharged from one of eight hospitals in north central Alabama between October 1989 and September 1992. Data were derived from a retrospective acute-care medical record review and 12-month annual follow-up telephone interviews. The findings indicate that high self-efficacy is significantly associated with less severe neurological impairment, being white, employed at injury, having a high-school education or beyond, and having an unintentional injury. In terms of marital status our data indicate the odds of divorced persons having high self-efficacy are 8.2 (CL = 0.919, 74.1) times those of married persons. In addition, 64% of those who were divorced during the 12 months after injury had high self-efficacy compared to 50% of those who were divorced prior to injury.

Activities of Daily Living↗
PubMed1998

Auditory brainstem responses in a Rhesus Macaque model of neuro-AIDS.

Nine rhesus macaques (Macaca mulatta) were inoculated with a combination of two passaged strains of SIVmac (R71 and 17E), both of which are known to be neurovirulent. Auditory brainstem responses (ABRs) were recorded at regular intervals from these animals both before and after inoculation. Increases in ABR peak and interpeak latency were observed corresponding to progression of SIV disease. Post-inoculation increases in latency were observed for all five peaks of the ABR and for interpeak intervals I-V and III-V. The largest increases in latency were associated with end-stage disease. Within 14 weeks of inoculation, all but two animals developed end-stage simian AIDS and were euthanized. Histopathological examination revealed multifocal lesions in the cerebral gray and white matter as well as in the auditory structures of the brainstem. In most animals, ABR changes were accompanied by evidence of underlying neuropathology. However, cases of severe neuropathology with no ABR abnormalities and vice versa were also noted. Though in a much shorter time frame, SIVmac R71/17E produced both physiological and histopathological abnormalities similar to those associated with HIV disease in humans. These results further support the SIVmac R71/17E infected rhesus macaque as an animal model of HIV related neurological disease in humans.

AIDS Dementia Complex↗
PubMed1997

Socioeconomic determinants of health: community marginalisation and the diffusion of disease and disorder in the United States.

This article describes the cascading diffusion of "inner city problems" of disease and disorder in the United States--from the huge marginalised inner city communities of the largest municipalities, first along national travel routes to smaller cities, and then from central cities into surrounding more affluent suburbs-following the pattern of the daily journey to work. Public policies and economic practices which increase marginalisation act to damage the "weak ties" of the community social networks which bind central city neighbourhoods into functioning units. Spreading disease and disorder can be interpreted as indices of the resulting social disintegration, which is driven by policy. This "failure of containment" in the United States should serve as a warning for cities in Europe against reducing the municipal and other services that they provide to "unpopular" subpopulations.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Factors associated with awareness of vocational rehabilitation services after traumatic brain injury.

OBJECTIVES: To determine the characteristics of persons with traumatic brain injury (TBI) who were aware of vocational rehabilitation (VR) services 1 year after hospital discharge. DESIGN: Medical record and longitudinal survey data on persons with TBI were analyzed using logistic regression and bivariate analyses. SETTING: The study sample was drawn from a population-based sample of persons hospitalized in 1 of 8 hospitals in north-central Alabama. PARTICIPANTS: Criteria for inclusion were: (1) being at least 18 years of age or older when injured; (2) having sustained a TBI; (3) being discharged alive after a hospital stay of at least 3 days; (4) residing and having been injured in the state of Alabama; (5) participation in a 12-month follow-up interview. MAIN OUTCOME MEASURE: Patients' awareness of VR service programs and benefits. RESULTS: Awareness of VR service programs was associated with: (1) being Caucasian; (2) being more often employed at the time of injury; (3) being more often severely injured; and (4) more frequently receiving outpatient rehabilitation. CONCLUSION: Interventions should target non-Caucasians, those who were unemployed when injured, those less severely injured, and those not receiving outpatient rehabilitation services after hospital discharge. Periodic review of VR benefits with patients and their families should be undertaken by health care and VR professionals.

Adult↗
PubMed1997

Differential regulation of genes encoding synaptic proteins by the Oct-2 transcription factor.

In order to investigate the effect of the Oct-2 POU family transcription factor on the regulation of genes encoding synaptic proteins, we have used cell lines in which the level of Oct-2 has been greatly reduced using an antisense approach. The reduced Oct-2 level results in enhanced expression of SNAP-25 and synapsin I, indicating that the genes encoding these proteins are normally repressed by Oct-2 in neuronal cells. In contrast, no alteration was observed in the levels of the synaptic proteins, synaptophysin and synaptotagmin. Although the neuronal forms of Oct-2 can repress the synapsin I promoter in co-transfection experiments, indicating that they have a direct effect on the expression of this gene, they have no effect on the activity of the SNAP-25 promoter, indicating that the effect of Oct-2 on this gene is likely to be indirect. These effects are discussed in terms of the differential effect of Oct-2 and the related POU family transcription factor Brn-3a, on the promoters of genes encoding different synaptic proteins.

Animals↗
PubMed1997

The hierarchical diffusion of AIDS and violent crime among U.S. metropolitan regions: inner-city decay, stochastic resonance and reversal of the mortality transition.

Census data on migration within and between the 25 largest U.S. metropolitan areas-containing more than 113 million people-permit construction of a probability-of-contact matrix corresponding to a particular Markov process dominated by the nation's largest cities, a hierarchical structure. Regression models based on vectors associated with that process find the large-scale diffusion of AIDS in the U.S.A. depends strongly on national patterns of contact with the original AIDS outbreaks in New York City and San Francisco as modulated by the violent crime rate, a local index of social disintegration resulting from the marginalization of minority ethnic urban communities. Violent crime is itself undergoing a recognizably similar hierarchical diffusion from the largest U.S. cities into smaller metropolitan regions. Further analysis suggests that continuation of public policies of "benign neglect" and "planned shrinkage" directed against marginalized urban populations may trigger a strong stochastic resonance which can significantly degrade public health and public order for much of the three-quarters of the U.S. population living in or near cities, in effect reversing the mortality transition of the last century.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Psychometric evaluation of the Organizational Job Satisfaction Scale.

Findings are reported from a replicated evaluation of the psychometric properties of the Organizational Job Satisfaction Scale. Data lend strong support for the scale which assesses four dimensions of organizational job satisfaction. Principal component factor analysis of data from two independent samples of urban staff registered nurses (RNs) (n = 496; n = 532) confirmed four dimensions of pay, interaction, administration, and status. Cronbach's alpha for subscales ranged from .76 to .88. Pearson correlation coefficients for the interrelationships among subscales and an estimate of theta verified internal consistency. The Organizational Job Satisfaction Scale scores correlated significantly with a criterion measure of job enjoyment. Hypothesis testing of theoretically predictable relationships supported construct validity. Scores on the organizational job satisfaction subscales correlated significantly with automony, stress, and commitment. Item revisions and recommendations for future use of the instrument are discussed.

Adult↗
PubMed1996

Differential regulation of the two neuronal nitric-oxide synthase gene promoters by the Oct-2 transcription factor.

The Oct-2 transcription factor has been shown previously to repress both the cellular tyrosine hydroxylase and the herpes simplex virus immediate-early genes in neuronal cells. Here we identify the gene encoding the neuronal nitric-oxide synthase (nNOS) as the first example of a gene activated in neuronal cells by Oct-2. The levels of the nNOS mRNA and protein are greatly reduced in neuronal cell lines in which Oct-2 levels have been reduced by an antisense method, although these cells have enhanced levels of tyrosine hydroxylase. Moreover, the nNOS gene regulatory region is activated by Oct-2 expression vectors upon cotransfection into both neuronal and non-neuronal cells, and this response is dependent upon a 20-amino acid region within the COOH-terminal activation domain of Oct-2. Of the two closely linked promoters that drive nNOS gene expression, only the downstream 5.1 promoter is activated by Oct-2, whereas the 5.2 promoter is unaffected. These effects are discussed in terms of the potential role of Oct-2 in regulating nNOS expression in the nervous system.

Animals↗
PubMed1996

Using reflective diaries to assess students.

This article looks at the problems of using reflective diaries to conduct formative assessments of students' performance. The author highlights the importance of the proper definition of terms, and suggests there are strengths and limitations associated with attaching significance to retrospective, reflective self-assessment.

Education, Nursing↗
PubMed1996

Experiential learning and critical thinking in nursing.

This article describes a continuing ethnographic study of critical thinking, reflection and experiential learning in nursing. The author examines the related theory and explains the terms of reference which underpin the study. Date analysis so far emphasises the importance of recognising positive and negative feelings associated with experiences, when engaging in reflection. She also outlines the precursors to effective and non-effective reflection implied by the data. It is suggested that there is no correct model for critical thinking and the author highlights the need for further research into effective and non-effective outcomes of reflection.

Education, Nursing↗