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Biomedical subjects

A P Smith

Publications and source records attributed to A P Smith.

At least 19 recordsLinked to original sources
PubMed2005

A community based investigation of the association between cannabis use, injuries and accidents.

There are well documented acute and chronic effects of cannabis use. However, less is known about any effects on safety within the context of work and everyday life. The aim of the study was to examine any association between cannabis use and injuries and accidents. A postal questionnaire survey was conducted among people selected at random from the electoral registers of Cardiff and Merthyr Tydfil. Cannabis use was associated with both minor injuries and accidents, particularly among those with high levels of other associated risk factors. Cannabis use was associated with a significant detrimental impact on safety. It is possible that this is linked to an amplification of other risk factors associated with accidents and injuries. This has potentially wide reaching implications particularly in the context of other work and lifestyle characteristics.

Accidents↗
PubMed2005

Cannabis use, cognitive performance and mood in a sample of workers.

There are well documented acute and chronic effects of cannabis use on mental functioning. However, less is known about any effects on cognition within the context of work and everyday life. The aim of the study was to examine any association between cannabis use and cognitive performance, mood and human error at work. Cannabis users and controls completed a battery of laboratory based computer tasks measuring mood and cognitive function pre- and post-work at the start and end of a working week. They also completed daily diaries reporting their work performance. Cannabis use was associated with impairment in both cognitive function and mood, though cannabis users reported no more workplace errors than controls. Cannabis use was associated with lower alertness and slower response organization. In addition, users experienced working memory problems at the start, and psychomotor slowing and poorer episodic recall at the end of the working week. This pattern of results suggests two possible effects. First a 'hangover'-type effect which may increase with frequency of use. Second a subtle effect on cognitive function, perhaps more apparent under cognitive load and/or fatigue, which may increase with more prolonged use. The results also highlight the importance of the timing of testing within the context and routine of everyday life.

Adolescent↗
PubMed2005

Brain mechanisms for mood congruent memory facilitation.

Emotional information is better remembered when mood at the time of retrieval matches it in valence (positive mood, positive material). An associative memory model predicts that this 'mood congruent' facilitation is due to the mood-related reactivation at retrieval of emotional responses which were linked to valenced information at encoding. To test this model, we presented subjects with positive and negative words at study and manipulated their mood at test while using functional imaging to monitor brain activity. Subjective mood ratings and heart rate variability both indicated that the manipulation was effective, and memory performance showed a strong trend towards facilitation in congruent conditions. In the functional imaging data, valence-specific conjunctions between encoding activity predicting subsequent memory in a congruent mood and retrieval activity relating to mood congruent recollection revealed shared responses in subgenual cingulate for positive valence and posteriolateral orbitofrontal cortex for negative valence, thus supporting the associative model. To elucidate the mnemonic basis of facilitation, independent of valence, we examined the shared correlates of positive and negative congruence and found that parts of the episodic memory system were activated by congruence in correct rejection trials, but no part of this system was activated by congruence in correctly remembered trials. This pattern suggests that mood congruent facilitation occurs at the level of attempted recall rather than that of successful recollection.

Adult↗
PubMed2005

Psychotropic medication use and accidents, injuries and cognitive failures.

BACKGROUND: Psychotropic medication has the potential to impair psychomotor and cognitive function, and several medications have well documented links to increased accident and injury susceptibility. Those developed more recently have many fewer side effects. However, there is little work examining any association between psychotropic medication use and safety within the context of other demographic, health and lifestyle factors. AIMS: To examine and compare any associations between psychotropic medication use (including benzodiazepines, tricyclics and SSRIs) and accidents, injuries and cognitive failures in a community sample. METHODS: A postal questionnaire survey was conducted among people selected at random from the electoral registers of Cardiff and Merthyr Tydfil. RESULTS: Psychotropic medication use was associated with accidents, injuries and cognitive failures, particularly among those who already had higher levels of other risk factors and/or continuing mental health problems. CONCLUSIONS: The well established associations between accidents and injuries and older psychotropic medications were replicated. SSRIs, however, were relatively safer. The study also highlighted the need to consider any effect of psychotropic medication within the context of both mental health status and other factors.

Accidents↗
PubMed2003

Use of a mandibular advancement device in obstructive sleep apnoea.

The present study investigated the effectiveness of an intra-oral mandibular advancement device in the treatment of patients with obstructive sleep apnoea (OSA) who could not tolerate or who had failed to comply with continuous positive airway pressure (CPAP). Thirty-five patients diagnosed by sleep study as suffering from OSA, who had either been unable to tolerate or had been non-compliant with CPAP treatment, were included in the study. The subjects completed an Epworth sleep questionnaire. The subjects then had an oral appliance made. After using the appliance for 3 months, the patients repeated the questionnaires and had a repeat sleep study performed with the oral appliance in situ. Thirty-one subjects completed the investigation. Mean AHI pre- and post-study were 26.64 and 24.06, respectively (P > 0.05). Mean Epworth scores pre- and post-study were 16.32 and 14.64, respectively (P > 0.05). Those patients with a pre-study AHI < 20 (n = 23), however, did significantly better with the appliance (P < 0.0001). Those patients with a pre-study AHI > 20 did not benefit from this device (P > 0.05). The main problems encountered were initial jaw discomfort in 18 patients and dry mouth in 11 patients (both of which improved with continued usage). It was concluded that the type of appliance used in this study can be recommended for those with mild OSA who are unable to tolerate CPAP.

Female↗
PubMed2003

Breakfast cereal consumption and subjective reports of health by young adults.

The aim of the present research was to extend previous research which has shown that consumption of breakfast is associated with reports of better health. Previous research has confirmed this in samples in the age ranges from mid-twenties to early eighties. The present study considered young adults (189 volunteers, aged between 19-21 years, mean age 19.6 years) living at home. The results showed that skipping breakfast is associated with reports of poorer health and that regular breakfast cereal consumption is associated with better reported health. The effects of breakfast could not be explained by other health-related behaviours or other aspects of diet. Further research is now required to determine the mechanisms underlying this robust association to examine whether it is observed with objective indicators of health and specific diseases.

Adult↗
PubMed2003

The Bristol Stress and Health Study: accidents, minor injuries and cognitive failures at work.

BACKGROUND: Accidents and injuries at work account for several million working days lost each year. Cognitive failures (problems of memory, attention or action) can lead to accidents and injuries in certain contexts. AIM: This work describes the prevalence and associations of workplace accidents, minor injuries and cognitive failures reported by respondents to a follow-up postal questionnaire as part of the community-based Bristol Stress and Health Study. METHODS: Postal questionnaires were sent to 4673 people who participated in the first phase of the study (in which questionnaires were sent to individuals selected at random from the electoral roll). RESULTS: Four per cent of workers reported an accident at work, 8% reported quite or very frequent minor injuries and 13% reported quite or very frequent cognitive failures. Accidents at work were associated with being male, smoking and higher negative job characteristics. Respondents reported workplace accidents at a level similar to the overall UK rate. Accidents and minor injuries, and minor injuries and cognitive failures, shared common associations and all three outcomes were associated with each other. CONCLUSION: Information about cognitive failures is important in the study of accidents and injuries at work. In addition, negative job characteristics represent part of the context in which human error is translated into injury.

Accidents, Occupational↗
PubMed2002

Outpatient intensive chemotherapy for small cell lung cancer: five years experience of modified 'ICE' ifosfamide carboplatin and etoposide.

INTRODUCTION: Small Cell Lung Cancer (SCLC) is increasingly being treated in the district general hospital setting. The search for an active regimen which can be given with the least toxicity and best outcomes led us to use a modified ICE (Ifosfamide, Carboplatin and Etoposide) regimen and modify it further by using oral mesna instead of intravenous mesna. METHOD: All patients selected to receive the modified ICE regime over a 5-year period were included in our study. All patients were assessed for performance status and prognostic factors. Only those with WHO performance status 0-1 and Manchester prognostic score 0-3 were considered for ICE chemotherapy. All patients were followed up for 1 year after recruitment was completed. RESULTS: Median survival for all 32 patients was 18.4 months (CI 12.2-24.6) and for the 28 patients with limited disease the median survival was 19.9 months (CI 8.2-31.6). Toxicity levels were low with no neutropenic deaths. One patient died three days after treatment was started due to disease progression. A total of 6 patients remained alive one year after recruitment was completed. Five out of the 6 were followed up for at least 2 years. CONCLUSION: Using this out-patient modified ICE regime we have achieved a median survival comparable to other active chemotherapy regimes for SCLC with no significant increase in toxicity.

Administration, Oral↗
PubMed2002

Stress, breakfast cereal consumption and cortisol.

Recent research has shown that regular consumption of breakfast cereal is associated with lower stress levels and reports of better physical and mental health. The present study examined this issue using an objective indicator of stress, salivary cortisol. The results showed that stress was associated with higher cortisol levels and daily consumption of breakfast cereal was associated with lower cortisol levels. Although it was not possible to rule out all the alternative explanations of the association between breakfast cereal consumption and cortisol, analyses did show that the effect could not be accounted for by general health or nutritional status. The effects of breakfast cereal consumption and stress were also independent, which shows that the effects of breakfast found here cannot be due to stress buffering. Further research manipulating the nutrient content of the breakfast cereal is now required to provide further information about the mechanisms underlying this effect.

Adult↗
PubMed2002

Stress, breakfast cereal consumption and objective signs of upper respiratory tract illnesses.

Recent research has shown that both negative life events and breakfast cereal consumption are associated with the incidence and severity of subjective symptoms of upper respiratory tract illnesses (URTIs) Two studies were conducted to examine whether objective markers of illness were also associated with stress and breakfast cereal consumption. The results from the first study showed that regular breakfast cereal consumption was associated with lower sub-lingual temperatures in volunteers with URTIs. Stress had no effect on temperature. In the second study nasal secretion weight was lower in regular breakfast cereal consumers but was not influenced by stress. These studies suggest that breakfast cereal consumption is associated with reduced illness severity and that this does not reflect stress levels. Further research is now required to determine whether such results are directly due to cereal consumption or reflect correlated attributes, such as other aspects of the diet.

Body Temperature↗
PubMed2002

Measuring the meaning of disability in rheumatoid arthritis: the Personal Impact Health Assessment Questionnaire (PI HAQ).

BACKGROUND: Measurement of disability in rheumatoid arthritis is often used to support treatment decisions and outcome assessments, but is used without reference to the impact of disability on individual patients. OBJECTIVE: To develop and validate a scale to measure individual values for functions, which is used to weight the level of an individual patient's functional loss and thus calculate the personal impact of disability. METHODS: In four linked studies, first the phraseology for values was explored to develop a stem question for the value scale couched in terms patients understand (face validity). Then short and long versions of the value scale were compared (content validity) and tests of internal consistency and short term reliability undertaken (criterion validity). Finally, the value scale was examined for long term reliability and agreement with expected variables (criterion and construct validity), after which personal impact scores were calculated and their construct validity examined. RESULTS: Patients understand the concept of values, and a positively phrased stem question was developed for the value scale, for which a short version was reasonably equivalent to a long version. The value scale was reliable over one week (96% changed by <1 point) with positive interitem correlation. Reasonable six and 12 month reliability was shown (52% changed by <0.5 points), and the value scale was independent of disability and clinical, psychological, personality, and social support variables. Personal impact scores were then calculated by using the value scores to weight disability scores. Impact scores varied widely between patients of similar disability. Personal impact for disability showed convergent validity with dissatisfaction with disability, perceived increase in disability, increased disease activity, worse psychological status, low social support, and time trade off for disability. It discriminated between patients with low and high dissatisfaction with disability, life satisfaction, depression, pain, and helplessness. CONCLUSION: This individualised personal impact scale should lend meaning to disability scores, improving the interpretation of clinical and research data.

Activities of Daily Living↗
PubMed2001

Combinatorial study of surface pattern formation in thin block copolymer films.

Surface pattern formation in diblock copolymer films is investigated as a function of film thickness h and molecular mass M. Smooth films are observed for certain h ranges centered about multiples of the lamellar thickness L0, and we attribute this effect to an increase in the surface chain density with h in the outer brushlike copolymer layer. We also observe apparently stable labyrinthine surface patterns for other h ranges, and the average size of these patterns is found to scale as lambda approximately L0(-2.5). Hole and island patterns occur for h ranges between those of the labyrinthine patterns and the smooth regions, and their size similarly decreases with L0 and M.

Journal Article↗
PubMed2001

Optimization of scanning transmission X-ray microscopy for the identification and quantitation of reinforcing particles in polyurethanes.

The morphology, size distributions, spatial distributions, and quantitative chemical compositions of co-polymer polyol-reinforcing particles in a polyurethane have been investigated with scanning transmission X-ray microscopy (STXM). A detailed discussion of microscope operating procedures is presented and ways to avoid potential artifacts are discussed. Images at selected photon energies in the C 1s, N 1s and O 1s regions allow unambiguous identification of styrene-acrylonitrile-based (SAN) copolymer and polyisocyanate polyaddition product-based (PIPA) reinforcing particles down to particle sizes at the limit of the spatial resolution (50 nm). Quantitative analysis of the chemical composition of individual reinforcing particles is achieved by fitting C 1s spectra to linear combinations of reference spectra. Regression analyses of sequences of images recorded through the chemically sensitive ranges of the C 1s, N 1s and O 1s spectra are used to generate quantitative compositional maps, which provide a fast and effective means of investigating compositional distributions over a large number of reinforcing particles. The size distribution of all particles determined by STXM is shown to be similar to that determined by TEM. The size distributions of each type of reinforcing particle, which differ considerably, were obtained by analysis of STXM images at chemically selective energies.

Microscopy, Electron, Scanning↗
PubMed2001

A CDK-independent function of mammalian Cks1: targeting of SCF(Skp2) to the CDK inhibitor p27Kip1.

The Cks/Suc1 proteins associate with CDK/cyclin complexes, but their precise function(s) is not well defined. Here we demonstrate that Cks1 directs the ubiquitin-mediated proteolysis of the CDK-bound substrate p27Kip1 by the protein ubiquitin ligase (E3) SCF(Skp2). Cks1 associates with the F box protein Skp2 and is essential for recognition of the p27Kip1 substrate for ubiquitination in vivo and in vitro. Using purified recombinant proteins, we reconstituted p27Kip1 ubiquitination activity and show that it is dependent on Cks1. CKS1-/- mice are abnormally small, and cells derived from them proliferate poorly, particularly under limiting mitogen conditions, possibly due to elevated levels of p27Kip1.

Amino Acid Motifs↗
PubMed2001

Decrease of psychomotor performance in subjects with latent 'asymptomatic' toxoplasmosis.

Toxoplasma gondii is known to induce specific behavioural changes in its intermediate hosts. This is usually considered to be an evolutionary adaptation aimed to increase the probability of transmission of the parasite into its definitive host, the cat, by predation. In rodents an increase of reaction time as well as many other specific behavioural patterns have been observed. Here we report the results of our double blind study showing the significantly longer reaction times of 60 subjects with latent toxoplasmosis in comparison with those of 56 controls. Moreover, the existence of a positive correlation between length of infection and mean reaction time suggested that slow and cumulative effects of latent toxoplasmosis rather than a one-step (and possibly transient) effect of acute toxoplasmosis disease are responsible for the decrease of psychomotor performance of infected subjects. To our knowledge, this is the first study confirming the existence of such parasite-induced changes in human behaviour that could be considered in evolutionary history of the human species as adaptive from the point of view of parasite transmission.

Animals↗
PubMed2001

Disclosing a diagnosis of Alzheimer's disease: patient and family experiences.

BACKGROUND: Informing patients and families about the diagnosis of Alzheimer's disease (AD) is a complex ethical and practical issue. This qualitative study explores the psychosocial impact of disclosing a diagnosis of AD on patients and family members. METHODS: This study identified 14 patients and their accompanying family members undergoing a multidisciplinary assessment for dementia at an outpatient clinic for AD and related disorders. Of the group, three patients had probable AD and five had possible AD as per NINCDS-ADRDA criteria. Six patients were not demented as per DSM IIIR criteria. Disclosure of diagnosis occurred, in a family conference, within six to eight weeks of the assessment. Data collection methods included observation of the assessment and the family conference as well as in-depth home interviews with family members and with each patient whenever feasible. The interviews were transcribed verbatim and coded for recurrent themes. RESULTS: A total of 40 individuals across 14 families participated in this study. Only two families chose not to have the patient attend the family conference. The disclosure of a diagnosis of probable AD brought on an experience of relief in three families, marking the end of a lengthy period of confusion about the nature of memory problems. Patients diagnosed with possible AD and their families interpreted how indicative the diagnosis was of the presence of the disease with varying degrees of certainty depending on pre-assessment beliefs about the cause of memory problems. In the group diagnosed as not demented, four patients had complaints of forgetfulness likely related to minor depression. The disclosure of a diagnosis of no dementia did not produce the anticipated relief. Two patients continued to believe their memory problems were caused by the early onset of AD or some other "organic" problem. INTERPRETATION: This study reveals that disclosure of the diagnosis of AD to patients and family members is generally beneficial but that there are variations in the understanding of the diagnostic information, particularly in instances where the assessment results are ambiguous.

Aged↗
PubMed2001

A prospective longitudinal study of growth velocity in twin pregnancy.

OBJECTIVES: Fundamental research into the growth of twins is lacking. Twin growth in utero is commonly assumed to follow similar patterns of growth as that of singletons. This preliminary descriptive study on twin pregnancy aimed to define growth velocity as gestation advances, and to study if twin order, fetal sex, zygosity and chorionicity have any relationship to growth velocity. METHODS: One hundred and sixty-two women with twin pregnancies had an ultrasound examination at fortnightly intervals from 16 weeks until delivery. Fetal measurements of biparietal diameter, abdominal circumference and femur length were performed at each examination. Growth velocity for each parameter was defined as the difference in measurements for that parameter divided by the time interval between measurements. Postnatally, zygosity and chorionicity were determined by genetic fingerprinting and inspection of the placenta, respectively. RESULTS: Growth velocity for all parameters decreased as gestation advanced, with the downward trend more noticeable after 32 weeks. Maximum and minimum growth occurred at 22-23 weeks and 36-37 weeks, respectively. Maximum and minimum growth velocities for the abdominal circumference were 1.7 and 0.8 cm/week, respectively. Birth order, fetal sex, chorionicity and zygosity were not related to growth velocity. CONCLUSIONS: These preliminary results suggest that growth velocity in twins decreases after 32 weeks' gestation. It appears that growth velocity is independent of birth order, fetal sex, chorionicity and zygosity.

Anthropometry↗