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Biomedical subjects

P Tyler

Publications and source records attributed to P Tyler.

15 recordsLinked to original sources
PubMed2001

Ammonium extraction method for ion chromatographic measurements of disc drive components.

The analysis of ionic micro-contamination is of growing importance in the disc drive industry. Through the use of ion chromatography, cleanliness of drive components can be assessed. An objective to improve quantification of highly reactive inorganic ions that exist within the drive environment was implemented. This paper presents a new extraction technique used to determine low levels of ammonium, by microbore ion chromatography. Various chemical compounds within adhesive formulations can be a source of extractable ammonium. By combining this new extraction method with ion chromatography, the percentage of different chemical compounds within adhesive formulations was correlated to the level of extractable ammonium observed.

Chromatography, Liquid↗
PubMed1999

Abnormalities of internally generated saccades in obsessive-compulsive disorder.

BACKGROUND: We aimed to utilize tests of saccadic function to investigate whether cognitive abnormalities in obsessive-compulsive disorder (OCD) arise from a dysfunction of inhibitory processes or whether they reflect a more general difficulty in guiding behaviour on the basis of an internal representation of task goal. METHODS: Twelve patients with OCD and 12 matched controls performed a visually-guided saccade task, a volitional prosaccade task and an antisaccade task. The latency and gain of saccades was compared between groups for the three saccade tasks. The number of antisaccade errors was also calculated and compared between groups. RESULTS: There was no difference for antisaccade error rates between the groups. The latency of visually guided saccades did not differ between groups, however the latency of both volitional prosaccades and antisaccades was significantly slower in the patients with OCD than in controls. The difference in latency between volitional prosacades and antisaccades, however, was equal between groups. CONCLUSIONS: These results suggest that patients with OCD have an abnormality in guiding behaviour on the basis of an internal representation of the task goal, rather than a problem with inhibiting reflexive behaviour.

Adult↗
PubMed1999

Norms and the effects of demographic variables on a neuropsychological battery for use in healthy ageing Australian populations.

OBJECTIVE: The current study examined the performance of a healthy ageing population on the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological test battery in order to determine norms for use in an Australian setting. The effects of age, education, gender and mood on cognitive performance in healthy older individuals were also explored. METHOD: The CERAD neuropsychological battery was administered to a sample of healthy elderly subjects (n = 243). Subjects also completed an anxiety inventory and a depression scale. Means and standard deviations of different age, gender and education groups are reported as normative data. A Principal Components Analysis (PCA) was also calculated. Linear regression was applied to the five factors extracted from the PCA using age, education, gender and mood as independent variables. RESULTS: All recorded means were within 1 SD of those reported in the original CERAD normative study. Five factors that loaded on measures of memory and learning, language, praxis and executive function were extracted. The independent variables age, education and gender all had significant effects on cognitive performance. However, mood had no such effect. CONCLUSIONS: Risk factors for cognitive decline indicated by the CERAD battery include age, education and gender. Anxiety and depression are not associated with CERAD cognitive performance. The CERAD battery is a valid and reliable neuropsychological tool that may assist in the detection and diagnosis of Alzheimer's disease in Australian populations.

Adult↗
PubMed1999

The effects of age and mood on saccadic function in older individuals.

To investigate the effect of age and mood on saccadic function, we recorded prosaccades, predictive saccades, and antisaccades from 238 cognitively normal, physically healthy volunteers aged 44 to 85 years old. Mood levels were measured using the State-Trait Anxiety Inventory and Center for Epidemiological Studies Depression Scale inventories. Small, but significant, positive relationships with age were observed for the mean latency and associated variability of latency for all types of saccades, as well as the antisaccade error rate. Saccade velocity or accuracy was unaffected by age. Increasing levels of depression had a minor negative influence on the antisaccade latency, whereas increasing levels of anxiety raised the antisaccade error rate marginally.

Adult↗
PubMed1998

Neurological and cognitive abnormalities associated with chronic petrol sniffing.

Substance abuse through the deliberate inhalation of petrol (petrol sniffing or gasoline sniffing) is prevalent in inner-urban and remote rural communities. Although acute toxic encephalopathy is a well-documented consequence of petrol sniffing, the neurological and cognitive effects of chronic petrol sniffing are unknown. A structured neurological examination and the Cambridge Neuropsychological Test Automated Battery (CANTAB) were used to assess neurological and cognitive function in 33 current-sniffers (individuals who had sniffed petrol for >6 months), 30 ex-sniffers (individuals who had sniffed petrol in the past but had abstained for 6 months) and 34 matched non-sniffers (individuals who had never sniffed petrol). No subject was, or had been, encephalopathic from petrol sniffing and all were residing in their community. Blood lead and hydrocarbon levels and information about petrol sniffing behaviour were obtained from each subject. When compared with non-sniffers, current-sniffers showed higher rates of abnormal tandem gait, rapid alternating hand movements, finger to nose movements, postural tremor, bilateral palmomental reflexes and brisk deep reflexes. Cognitive deficits occurred in the areas of visual attention, visual recognition memory and visual paired associate learning. Ex-petrol sniffers showed higher rates of abnormal tandem gait and bilateral palmomental reflexes and cognitive deficits in the areas of visual recognition memory and pattern-location paired associate learning. Blood lead levels and length of time of petrol sniffing correlated significantly with the magnitude of neurological and cognitive deficits. Blood hydrocarbon levels were not related to neurocognitive deficits, although this may have been due to methodological difficulties in obtaining hydrocarbon levels. These results suggest that subtle neurological and cognitive abnormalities do occur in individuals who abuse petrol but who do not have acute toxic encephalopathy and that the severity of these abnormalities is reduced with abstinence.

Adolescent↗
PubMed1997

Collection and normal levels of the amyloid precursor protein in plasma.

The amyloid precursor protein is contained in platelet alpha granules and released with degranulation. Methods are described to control for amyloid precursor protein release from platelets during blood collection and processing. In normal subjects (n = 97; age range, 44-84 years), the average plasma level of amyloid precursor protein was 6.5 +/- 1.8 ng/ml.

Adult↗
PubMed1996

Cognitive deficits in Machado-Joseph disease.

Cognitive function was examined in 6 patients with genetically confirmed Machado-Joseph disease (MJD) and 15 age- and ethnically matched controls using a series of subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB), a touch screen-based testing system previously validated in a number of movement and neurodegenerative disorders. The MJD patients had deficits in visual attentional function that were characterized by a slowing of the processing of visual information when task demands were high and an inability to shift attention to previously irrelevant stimulus dimensions to discriminate between complex stimuli. Tests of learning and visual memory were normal. These results demonstrate that specific cognitive deficits occur in patients with MJD, independent of motor dysfunction, and these deficits may reflect disruption to frontosubcortical pathways.

Adult↗
PubMed1996

Stress in clinical psychologists.

This paper summarises the findings of a series of studies of British clinical psychologists and discusses them in relation to the (mainly US) literature. Four main questions are addressed: (1) How stressed are clinical psychologists? (2) Which psychologists are most stressed? (3) What are the main sources of stress for clinical psychologists? and (4) What coping strategies are used by clinical psychologists? A figure summarises the main risk factors emerging from the literature which appear to be important mediators between the stressor and the psychological outcome variables. These are: (1) low job satisfaction; (2) low range of active coping strategies; (3) high use of avoidance coping strategies involving denial; (4) stressor not externalised and objectified; (5) stressor threatens other roles/relationships; (6) low experience in job; (7) no quality relationship with confidant(e)/poor quality relationship with partner; and (8) female.

Adaptation, Psychological↗
PubMed1989

Why forget the false positives?

Attention is drawn to the omission of the positive response tendencies from the data captured by prestigious clinical memory assessment devices. Data from a small pilot study, using alcohol abusers, suggest that this is potentially costly in terms of understanding and measuring dysfunction. There is also an indication that, by measuring with greater sensitivity to response patterns, it may be possible to identify memory dysfunction in alcohol abusers earlier in their abuse careers.

Adult↗
PubMed1988

Hospice care of the intravenous drug user AIDS patient in a skilled nurse facility.

We report on the initial experience in hospice care for a predominantly poor, black and Hispanic intravenous drug user AIDS population in New York City. Hospice care was provided in a skilled nursing facility with a certified hospice program delivering home care and inpatient care. A formal education program preceded patient admission to familiarize the staff and institution with AIDS issues. Between February 1986 and January 1988, 62 of 175 referred patients were accepted for hospice admission. The patients' mean age was 39 years and all had AIDS dementia complex. The mean length of stay was 35 days (range 1-280 days) and a total of 2011 days of hospice care was provided. Ninety-one percent of hospice days were spent on the inpatient unit; only 9% of hospice days were provided at home. Despite the requirement of expensive inpatient hospice care for most patient days, the estimated savings in decreased costs compared to acute hospital inpatient care was $751,488 for these 62 patients. Continuing fear of transmission among hospice staff was not a major problem; however, several unanticipated problems arose including (a) inability to provide home services, (b) continued drug abuse, (c) increased staff stress, (d) difficulty maintaining confidentiality, (e) difficult interactions with funeral directors, and (f) unsupportive and inappropriate funding requirements. Hospice care of AIDS patients is feasible, humane, and cost effective but problems of the intravenous drug using population require special attention and program modifications if hospice care is to be provided for this substantial and growing AIDS population.

Acquired Immunodeficiency Syndrome↗
PubMed1985

A comparison of dopamine, dobutamine and isoproterenol in the treatment of shock.

Twelve patients in shock, defined as being present if the mean arterial blood pressure was less than 60 mm Hg, pulmonary arterial occlusion pressure was 15 mm Hg or greater, urine output was 20 ml or less for 2 consecutive hours, and there was clinical evidence of poor peripheral perfusion, underwent a comparative therapeutic trial with dopamine at 200 micrograms . min-1 and 400 micrograms . min-1 (2.5-5.5 micrograms . kg-1 . min-1), dobutamine 250 micrograms . min-1 and 500 micrograms . min-1 (3.5-7 micrograms . kg-1 . min-1) and isoproterenol 2 micrograms . min-1 and 4 micrograms . min-1 (0.025-0.055 micrograms . kg-1 . min-1). Isoproterenol at 2 micrograms . min-1, produced a significant increase in pulse rate, cardiac output, left ventricular stroke work index and decrease in mean pulmonary blood pressure and pulmonary arterial occlusion pressure and at 4 micrograms . min-1 a significant increase in stroke volume, mixed venous oxygen tension and decrease in right atrial pressure and systemic vascular resistance was also observed. Dopamine at 200 micrograms . min-1 produced a significant increase in cardiac output, pulmonary arterial occlusion pressure and mixed venous oxygen tension and at 400 micrograms . min-1 a significant increase in pulse rate, mean arterial blood pressure mean pulmonary blood pressure, right ventricular stroke work index, right atrial pressure and pulmonary arterial occlusion pressure and decrease in arterial oxygen tension was also observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Developmental outcome of high-risk neonates in North Staffordshire.

The findings of the developmental outcome of a 2-year follow-up study (1982-1983) on 92 2 1/2-year-old children born in North Staffordshire District are reported. They were assessed by the Griffiths Mental Developmental Scales and all came from a defined geographical area. The babies were all cared for in the Neonatal Unit at the North Staffordshire Maternity Hospital. The group comprised infants weighing less than 1500 g and those of more than 1500 g who required ventilatory support for more than 48 hours. Nine (9.8%) children had major disabilities, including two with severe hearing impairment and two with visual impairment. Disabilities were not attributable to a congenital abnormality or illness acquired after discharge from the neonatal unit.

Blindness↗
PubMedDate not supplied

A measurement tool for assessing stress among mental health nurses.

There is growing evidence that nursing is a stressful occupation, particularly mental health nursing. However, the lack of an appropriate measurement tool has meant it has been difficult to investigate the nature of this stress. The aim of this study was to assess the efficacy of one such scale for measuring stress in mental health nurses, the Mental Health Professional Stress Scale. A total of six questionnaires was sent to a sample of 210 community and hospital mental health nurses. The findings suggested that the scale was a useful measure and predictor of stress. The most consistent predictor of poor mental health outcomes for nurses was home/work conflict, outweighing the significance of client/patient-related difficulties.

Adult↗