Biomedical subjects
J Hearn
Publications and source records attributed to J Hearn.
An overview of polymer latex film formation and properties.
The literature on polymer latex film formation has grown enormously in recent times--driven by the need to find alternatives for solvent-based systems with their adverse environmental impacts. Although greater insight has been shown by the use of modern instrumental techniques such as small angle neutron scattering, direct non-radiative energy transfer and atomic force microscopy, the actual mechanisms involved in deforming spherical particles into void-free films are still the subject of controversy and debate. Surfactant-free homopolymer model colloid latices, favoured in academic studies, together with latices containing surfactants whose redistribution can influence film properties, and the more complex copolymer, blended, core-shell and pigmented systems needed to satisfy a full range of film properties are all considered.
Investigating recovery from stroke: a qualitative study.
A recent randomized controlled trial evaluated the effects of specialist nurses providing information, advice and support to caregivers and patients at home during the first year after a stroke. Reported here are the results of a complementary study which used qualitative methods to examine the experience of patients and caregivers during the year of recovery after a stroke. We used semi-structured interviews with a purposively selected sample of 30 patients and 15 caregivers at the end of a randomized controlled trial (13-16 months post-stroke). Patients and caregivers provided vivid descriptions of the recovery process. Recovery was perceived in terms of the degree of congruence patients identified between their lives before, and after, stroke. Patients therefore had individual and personal yardsticks for measuring their recovery. In conclusion, further research and interventions must consider the diverse, complex, dynamic and highly personal character of stroke recovery. Traditional outcome measures are too simplistic to capture patients' and caregivers' experiences. There do not appear to be single or simple solutions to the problems of facilitating psycho-social adjustment.
Immunopathology of cerebral malaria: morphological evidence of parasite sequestration in murine brain microvasculature.
A murine model that closely resembles human cerebral malaria is presented, in which characteristic features of parasite sequestration and inflammation in the brain are clearly demonstrable. "Young" (BALB/c x C57BL/6)F(1) mice infected with Plasmodium berghei (ANKA) developed typical neurological symptoms 7 to 8 days later and then died, although their parasitemias were below 20%. Older animals were less susceptible. Immunohistopathology and ultrastructure demonstrated that neurological symptoms were associated with sequestration of both parasitized erythrocytes and leukocytes and with clogging and rupture of vessels in both cerebral and cerebellar regions. Increases in tumor necrosis factor alpha and CD54 expression were also present. Similar phenomena were absent or substantially reduced in older infected but asymptomatic animals. These findings suggest that this murine model is suitable both for determining precise pathogenetic features of the cerebral form of the disease and for evaluating circumventive interventions.
Palliative day care: what do services do? Palliative Day Care Project Group.
Palliative day care has expanded rapidly in the recent years, but the types of care available vary. To understand more about the different models of day care we conducted a questionnaire survey of the 43-day care centres in North and South Thames Regions in England (total population 13.75 million). The questionnaire covered: management, staffing and organizational policies; the numbers, types and reasons for referral; and the services and care provided. Forty (93%) centres responded. Centres had operated for between 1 and 16 years, mean 8 years. A total of 2268 day care places (mean per centre, 57) were available per week--with an estimated 1.77 places per 10,000 population. Twenty centres had never had a waiting list or had to prioritize patients; 30 had a discharge policy. The mean time the longest patient had been attending was 4.5 years, range 1-12 years. There were a total of 3627 new referrals per year or 3.06 per 10,000 population. Of the 2054 patients recorded by day care centres during a week of detailed monitoring, 1850 (90%) had cancer and 204 had other diseases--most commonly HIV or AIDS, motor neurone disease or stroke. Thirty-four centres were managed by nurses, two by social work or social service professionals, and the remainder by people with other backgrounds. Most units had doctors, nurses, chaplains, managers, aromatherapists and hairdressers, but occupational therapists, social workers, chiropodists, dietitians and music and art therapists were much more varied, as was whether these posts were paid. The most common activities were: review of patients' symptoms or needs, monitoring symptoms, bathing, wound care, physiotherapy, hairdressing and aromatherapy. Centres describing themselves as more or mostly social were less likely to undertake daily assessment of new symptoms and wound care (chi-squared 13.0, 10.1, respectively, df 4, P < 0.05). However, we found no significant differences between centres describing themselves as more medical or more social in reported levels of staffing, who was in charge, funding or most activities. The findings suggest that there are core activities offered in palliative day care, but also variations in medical assessments, nurse-led clinics, trips, art and music therapy, and artistic activities.
The cleaning of polymer colloids.
The current state of knowledge of the cleaning of polymer colloids is reviewed with regard to a wide range of cleaning and characterisation techniques. The type, level and quantity of impurities involved with different polymer latex formulations varies widely. Even for similar formulations, differences in the nature and number of functional groups reported are often a consequence of sometimes subtle differences in the cleaning procedures employed. Not only may surface functionality be affected but also monomer and oligomer extraction procedures may lead to morphological changes in the particles. No single technique alone is likely to be able to remove all impurities. Care is needed to avoid the introduction of new impurities from the equipment, materials and water used as well as possible contamination from atmospheric carbon dioxide, bacteria and fungi. These factors also need to be considered in the storage of latex particle standards.
Recovering from stroke: a qualitative investigation of the role of goal setting in late stroke recovery.
This article examines the role of goal setting in the continuing relationship between specialist nurse and patients recovering from stroke. The nurse intervention was intended to ease the patient through the stages of recovery from stroke, focusing on emotional and social recovery rather than physical function. Literature on the use of goals in the nursing process is discussed. The article uses data from contemporary nurse records and from interviews with nurses and with patients and caregivers. The data from each of these elements were subjected to content analysis and were then synthesized using a grounded theory approach to interpret their significance. The perspective of patients and caregivers provides an additional insight into the use and limitations of goal setting which is largely developed in the literature from a nursing perspective. Nurses were found to have different interpretations of the use of goal setting. Some used it explicitly in their relationships with patients, whilst others used the concept to inform their actions whilst being less explicit and more informal. In all cases they demonstrate the tension between establishing and supporting progress towards realistic recovery goals and recognizing the limitations now placed on stroke victims.
Development and validation of a core outcome measure for palliative care: the palliative care outcome scale. Palliative Care Core Audit Project Advisory Group.
OBJECTIVES: To develop an outcome measure for patients with advanced cancer and their families which would cover more than either physical symptoms or quality of life related questions. To validate the measure in various specialist and non-specialist palliative care settings throughout the UK. DESIGN: A systematic literature review of measures appropriate for use in palliative care settings was conducted. In conjunction with a multidisciplinary project advisory group, questions were chosen for inclusion into the scale based on whether they measured aspects of physical, psychological, or spiritual domains pertinent to palliative care, and whether similar items had shown to be valid as part of another measure. A staff completed version was developed to facilitate data collection on all patients throughout their care, and a patient completed version was designed to enable the patient to contribute to the assessment of their outcomes when possible. A full validation study was conducted to evaluate construct validity, internal consistency, responsiveness to change over time, and test-retest reliability. Assessments were timed. SETTING: Eight centres in England and Scotland providing palliative care, including inpatient care, outpatient care, day care, home care, and primary care. PATIENTS: A total of 450 patients entered care during the study period. Staff collected data routinely on patients in care long enough to be assessed (n = 337). Of these, 262 were eligible for patient participation; 148 (33%) went on to complete a questionnaire. MAIN MEASURES: The Palliative Care Outcome Scale (POS), the European Organisation for Research on Cancer Treatment, and the Support Team Assessment Schedule. RESULTS: The POS consists of two almost identical measures, one of which is completed by staff, the other by patients. Agreement between staff and patient ratings was found to be acceptable for eight out of 10 items at the first assessment. The measure demonstrated construct validity (Spearman rho = 0.43 to 0.80). Test/re-test reliability was acceptable for seven items. Internal consistency was good (Cronbach's alpha = 0.65 (patients), 0.70 (staff)). Change over time was shown, but did not reach statistical significance. The questionnaire did not take more than 10 minutes to complete by staff or patients. CONCLUSION: The POS has acceptable validity and reliability. It can be used to assess prospectively palliative care for patients with advanced cancer.
Systematic reviews.
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Do specialist palliative care teams improve outcomes for cancer patients? A systematic literature review.
The objective of the study was to determine whether teams providing specialist palliative care improve the health outcomes of patients with advanced cancer and their families or carers when compared to conventional services. The study involved a systematic literature review of published research. The source of the data included studies identified from a systematic search of computerized databases (Medline, psychINFO, CINAHL and BIDS to the end of 1996), hand-searching specialist palliative care journals, and studying bibliographies and reference lists. The inclusion criteria for articles were that the study considered the use of specialist palliative care teams caring for patients with advanced cancer. Articles were assessed and data extracted and synthesized, with studies graded according to design. A variety of outcomes were considered by the authors. These addressed aspects of symptom control, patient and family or carer satisfaction, health care utilization and cost, place of death, psychosocial indices and quality of life. Overall, 18 relevant studies were identified, including five randomized controlled trials. Improved outcomes were seen in the amount of time spent at home by patients, satisfaction by both patients and their carers, symptom control, a reduction in the number of inpatient hospital days, a reduction in overall cost, and the patients' likelihood of dying where they wished to for those receiving specialist care from a multiprofessional palliative care team. It was concluded that all evaluations were of services considered to be leading the field, or were pioneering training and treatments. However, when compared to conventional care, there is evidence that specialist teams in palliative care improve satisfaction and identify and deal with more patient and family needs. Moreover, multiprofessional approaches to palliative care reduce the overall cost of care by reducing the amount of time patients spend in acute hospital settings.
A multicenter evaluation of cancer pain control by palliative care teams.
Data on pain prevalence and severity were collected prospectively from advanced cancer patients as an integral part of two service evaluations. Six multidisciplinary palliative care teams working in Ireland formed the basis of one study and five teams based in the South of England were included in the second. A total of 695 cancer patients were referred and died in care in a minimum 6-month data collection period. Of these, 70% (486/695) were experiencing pain at referral to the services. After 2 weeks, there was a significant reduction (P < 0.0001) in the levels of pain experienced by patients, and no patient had overwhelming pain. The data emphasize that pain prevalence in advanced cancer patients cared for in the community is as high as that observed in other settings. Multidisciplinary palliative care teams are shown here to be effective in alleviating pain.
Outcome measures in palliative care for advanced cancer patients: a review.
Information generated using outcome measures to measure the effectiveness of palliative care interventions is potentially invaluable. Depending on the measurement tool employed the results can be used to monitor clinical care, carry out comparative research, provide audit data or inform purchasing decisions. However, the data collected can only ever be as good as the method used to obtain them. This review aimed to systematically identify and examine outcome measures that have been used, or proposed for use in the clinical audit of palliative care of patients with advanced cancer. Database searches were performed using MEDLINE (1991-1995), CANCERLIT (1991-1995), Healthplan (1985-1995), and 'Oncolink' on the internet. Further measures were located with the assistance of other professionals working in palliative care. The criteria for the inclusion and assessment of measures were a measure assessing more than one domain and a target population of advanced disease or palliative care Forty-one measures were identified, 12 of which satisfied the inclusion criteria. These contained between five and 56 items and covered aspects of physical, psychological and spiritual domains. Each measure meets some but not all of the objectives of measurement in palliative care, and fulfils some but not all of our criteria for validity, reliability, responsiveness and appropriateness.
A qualitative study of specialist nurse support for stroke patients and care-givers at home.
BACKGROUND: The involvement of five specialist nurses in providing a stroke support service was evaluated quantitatively in a recent randomized controlled trial. This complementary study used qualitative methods to evaluate trial outcomes more comprehensively. AIMS: To identify whether the nurses' intervention may have influenced the process of stroke recovery. METHOD: A purposefully selected subsample of 30 patients and 15 care-givers were interviewed within 1-3 months of their final quantitative assessment (12 months after recruitment to the randomized trial). Fifteen of the patients and eight of the care-givers had received visits from a specialist nurse. A semistructured interview was designed to include questions on perceptions of the recovery process and evaluation of services received. RESULTS: Some differences were evident between the accounts of control and intervention group subjects. The less tangible aspects of nurses' interventions--concern, attention, empathy and interest, when combined with sound professional knowledge, had identifiable value to the patients and care-givers. It appeared that the nurses had employed considerable sensitivity and skill in identifying and responding to particular needs at appropriate times. CONCLUSION: The qualitative evaluation offers a different picture to the quantitative results of the randomized controlled trial. In general, the findings of the qualitative study are more positive and encouraging than the quantitative results. The majority of patients and care-givers in the intervention group believed that they had benefited from the specialist nurse's visits.
Audit in palliative care: does practice change?
This study aimed to document current palliative care initiatives, identify any reported changes in working practice as a result of audit, and determine the opinions of palliative care staff towards audit. All 31 established palliative care services within the former North West Thames Regional Health Authority were sent a brief postal questionnaire on previous and current audit activities. Of the 28 units who responded, most (78%, n = 21) were currently involved in audit with a further 7% (n = 2) planning to implement audit in the near future. Changes as a result of audit included implementation of standards, for example response to referrals; improvements in documentation, for example revision of case notes; and changes to unit practice, such as converting to multidisciplinary care plans. The respondents viewed the main advantage of carrying out any audit project as the improvement or maintenance of the quality of patient care. The principal disadvantage expressed was the time-consuming nature of audit. An audit with a clear aim and thorough design can provide valuable evidence upon which new policies or strategies in palliative care can be based. By educating and training staff in audit and illustrating the benefits, any concerns about carrying out audit could be addressed.
Lack of influence of pretreatment antistreptokinase antibody on efficacy in a multicenter patency comparison of intravenous streptokinase and anistreplase in acute myocardial infarction.
Antistreptokinase antibodies present in patients as a result of previous streptococcal infections might theoretically influence the thrombolytic response to streptokinase or anistreplase. The potential influence of antibody, measured as antigen binding to immunoglobulin G, was investigated in a randomized, double-blind, multicenter patency comparison of intravenous streptokinase (1.5 million units/60 minutes) and intravenous anistreplase (30 units/2 to 5 minutes) in patients with acute myocardial infarction. Antibody results were evaluated in 333 patients (from a total study population of 370 patients) less than 76 years of age with ECG evidence of ST segment elevation who could be treated within 4 hours of the onset of symptoms. Variations in pretreatment circulating levels of antibody did not influence angiographically defined early coronary patency rates (Thrombolysis in Myocardial Infarction grade 2 or 3 perfusion, measured at a mean of 140 minutes after therapy was begun) for either streptokinase or anistreplase. Similarly the lytic response represented by systemic plasminogen activation and measured as changes in plasma plasminogen and fibrinogen levels after dosing (at mean times of 90 minutes and 24 hours) was not correlated with baseline antibody levels. Furthermore, pretreatment antibody was not a risk factor for poor outcome in response to streptokinase or anistreplase (reocclusion within 24 hours, in-hospital death, or stroke) and did not correlate with hypotension or allergic-type reactions recorded as adverse events. In conclusion, within the population limits defined by the inclusion and exclusion criteria of the study (patients were excluded if they had received streptokinase or anistreplase within the previous 6 months), pretreatment antistreptokinase immunoglobulin G is not a significant determinant of the efficacy response to streptokinase or anistreplase.
Comparison of the capsaicin- and amino acid-sensitivity of dorsal root C fibres in the rat and the toad.
1. The C elevation of the compound action potential (CAP) was recorded with suction electrodes from dorsal roots of rats at 25 degrees C and toads (Bufo bufo) at 10 degrees C. The C fibre CAP had a conduction velocity of 0.5 +/- 0.07 SE M per sec (N = 10) and 0.25 +/- 0.04 M per sec (N = 8) in the rat and toad nerves respectively. 2. The depressant effect of applied drugs on the amplitude of the C fibres CAP was measured. Nerves from both species had similar sensitivities to GABA. EC50 5.0 microM +/- 0.5 SEM (N = 3) and 5.5 microM +/- 1.4 (N = 3) for the rat and toad respectively. Maximum depressant effects of GABA produced in rat and toad nerves were 35% +/- 5 SEM and 17% +/- 2.5 respectively. 3. In five out of ten of the rat nerves tested kainate had a clear depressant effect (maximum 36% +/- 4.3 SEM, EC50 6.8 microM +/- 0.9 SEM, N = 3) on the C fibre CAP. Kainate, at concentrations from 100 to 500 microM, had no effect on seven toad nerves. 4. Toad nerves were about 100 times less sensitive, than rat nerves, to capsaicin (ED50 values 430 microM +/- 190 SEM and 0.7 microM +/- 0.2 respectively, N = 4). 5. The similar sensitivity of nerves in both species to GABA and differing sensitivities to kainate and capsaicin suggests that amphibian C fibres specifically lack sensitivity to capsaicin and kainate.
Rate of weight loss during underfeeding: relation to level of physical activity.
The kinetics and bioenergetic-metabolic determinants of weight loss were examined in obese women ingesting 900 kcal/d for 5 weeks. The patients were assigned either to a sedentary group (n = 5) or to an exercise group (n = 6) in which the participants expended an additional (X +/- SD) 346 +/- 61 kcal/d in aerobic physical activity. The percentage weight loss and the fractional rates (K1 = fast component; K2 = slow component) of weight loss were almost identical between the two groups. The failure of added exercise to increase the velocity of weight loss could not be explained by differences between the groups in any of the following: gastrointestinal energy and nitrogen (N) absorption; fractional rates of urinary urea N and total N loss; or the thermic effect of the formula diet. The cumulative and fractional rates of protein (ie N) loss were also similar between the groups. The exercise group lost more fat (5.3 +/- 1.0 kg) than the non-exercise group (4.4 +/- 1.6 kg, P less than .001) as measured by underwater weighing. The maximum between-group difference in the rate of fat loss, as determined by energy-N balance, occurred during early underfeeding. With continuation of the 900 kcal/d diet, the between-group differences in the rate of fat loss diminished. The exercise subjects significantly lowered their resting heat losses relative to the non-exercise subjects (P less than .025). This in turn reduced the degree of negative energy balance in the more energy-deficient exercise group.(ABSTRACT TRUNCATED AT 250 WORDS)
Myasthenia gravis caused by penicillamine and chloroquine therapy for rheumatoid arthritis.
We have described a unique patient who had reversible and dose-related myasthenia gravis after penicillamine and chloroquine therapy for rheumatoid arthritis. Although acetylcholine receptor antibodies were not detectable, the time course was consistent with an autoimmune process.