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Biomedical subjects

A Gray

Publications and source records attributed to A Gray.

At least 91 records · Page 5Linked to original sources
PubMed1999

Predicting cytomegalovirus disease after renal transplantation: an artificial neural network approach.

Outcome prediction is becoming increasingly important in medicine, but when a resource is scarce the need for accurate prediction becomes acute. Prediction based on biostatistical models has been in use for many years, but in areas such as renal transplantation their results have been disappointing. Recently however, there has been growing interest in the use of artificial neural networks for prediction. The creation of a large database containing high quality data on renal transplantation patients in Wales offers an ideal opportunity to research a new area viz., the ability of these techniques to accurately predict outcomes such as the appearance of disease in transplant recipients or the time to graft failure. This paper describes the use of neural networks to identify patients who risk the development of cytomegalovirus disease--a significant cause of mortality and morbidity in these patients. The neural networks we examined produced overall correct classifications well in excess of 80% in each of the two groups involved, diseased and non-diseased. These predictions are a considerable improvement on current methods and encourage the belief that renal transplantation data may respond well to analysis by neural networks.

Adolescent↗
PubMed1999

Follow-up of breast cancer in primary care vs specialist care: results of an economic evaluation.

A randomized controlled trial (RCT) comparing primary-care-centred follow-up of breast cancer patients with the current standard practice of specialist-centred follow-up showed no increase in delay in diagnosing recurrence, and no increase in anxiety or deterioration in health-related quality of life. An economic evaluation of the two schemes of follow-up was conducted concurrent with the RCT Because the RCT found no difference in the primary clinical outcomes, a cost minimization analysis was conducted. Process measures of the quality of care such as frequency and length of visits were superior in primary care. Costs to patients and to the health service were lower in primary care. There was no difference in total costs of diagnostic tests, with particular tests being performed more frequently in primary care than in specialist care. Data are provided on the average frequency and length of visits, and frequency of diagnostic testing for breast cancer patients during the follow-up period.

Breast Neoplasms↗
PubMed1999

Effects of recombinant ovine interferon tau, placental lactogen, and growth hormone on the ovine uterus.

Studies were conducted to determine effects of intrauterine administration of recombinant ovine interferon tau (IFNtau), placental lactogen (PL), and growth hormone (GH) on endometrial function. In the first study, administration of IFNtau to cyclic ewes for one period (Days 11-15) resulted in an interestrous interval (IEI) of approximately 30 days, whereas administration for two periods (Days 11-15 and Days 21-25) extended the IEI to greater than 50 days. Administration of IFNtau from Days 11 to 15 and of PL or GH from Days 21 to 25 failed to extend the IEI more than for IFNtau alone. In the second study, effects of IFNtau, PL, and GH on endometrial differentiation and function were determined in ovariectomized ewes receiving ovarian steroid replacement therapy. Endometrial expression of mRNAs for estrogen receptor (ER), progesterone receptor (PR), and oxytocin receptor (OTR) were not affected by PL or GH treatment; however, uterine milk protein mRNA levels and stratum spongiosum gland density were increased by both PL and GH treatments. Collectively, results indicated that 1) PL and GH do not regulate endometrial PR, ER, and OTR expression or affect corpus luteum life span; 2) down-regulation of epithelial PR expression is requisite for progesterone induction of secretory gene expression in uterine glandular epithelium; 3) effects of PL and GH on endometrial function require IFNtau; and 4) PL and GH regulate endometrial gland proliferation and perhaps differentiated function.

Animals↗
PubMed1999

Coitus-dependent family planning methods: observations from Bangladesh.

Some coitus-dependent methods of family planning, such as withdrawal, periodic abstinence, and the condom, require male involvement for their use, and using these methods in combination has proved to be sensible. An investigation of why male and female respondents in a survey conducted in Bangladesh often gave conflicting answers about which methods they were currently using, particularly about "traditional" methods and condoms, showed that inconsistency in their reports arose because these methods are used in combination to such an extent that they are difficult to distinguish. In order to obtain reliable responses about these methods, a survey approach different from the long-established one is required.

Adult↗
PubMed1999

Functional magnetic resonance image-guided surgery of tumors in or near the primary visual cortex.

OBJECTIVE: To assess the accuracy of functional magnetic resonance imaging (fMRI) of the primary visual cortex in patients undergoing surgery for tumors in the occipital lobe. METHODS: Two patients with nondominant occipital lobe tumors were studied, one with a solitary lung metastasis and another with radiation necrosis after radiosurgery for a low-grade astrocytoma. At surgery, visual evoked potentials (VEPs) were stimulated using Light-emitting-diode goggles and recorded using cortical grids placed immediately after brain exposure. The location of the peak VEP was compared to that predicted by the registered functional scan. RESULTS: In each case, the epicenter of visual activation as represented on the registered fMRI corresponded to the site of peak VEP recording. Prediction error for the visual cortex, measured in patient 1, was 1.0 mm. Visual confirmation showed the registration in the second patient to be accurate as well. CONCLUSION: As previously demonstrated for sensorimotor fMRI, visual fMRI accurately predicts the location of the primary visual cortex. Additional confirmation is expected with more clinical experience.

Adult↗
PubMed1999

Advance directives in a pediatric emergency department.

Parents of children with terminal illnesses are not always present when a life-threatening event occurs. For many of these children, an advance directive specifying alternate code orders has been written by the parent or legal guardian (hereafter the use of parent is to be interpreted as parent/legal guardian) and the patient's attending physician. Implementing a pediatric advanced directive presents significant problems for emergency personnel if the parent is not present to identify the existence of the directive and interpret the contents in the context of the current medical crisis.

Advance Directives↗
PubMed1999

Estimating long-term cost savings from treatment of Alzheimer's disease. A modelling approach.

OBJECTIVE: This paper puts forward a proposal for a modelling approach to the estimation of long term cost savings from the treatment of Alzheimer's disease (AD). DESIGN: In the proposed modelling approach, disease progression is defined in terms of intervals in the Mini-Mental State Exam (MMSE) scale. Clinical trial data are then used to determine the time at which a particular patient moved into a more severe stage of the disease. By comparing these durations across treatment groups, survival analysis is used to measure the impact of treatment in delaying the onset of a more costly stage of the disease. SETTING: Patients with varying severity of AD. PATIENTS AND PARTICIPANTS: The model uses clinical trial data on 1333 patients recruited internationally in 2 studies from 67 centres. INTERVENTIONS: The aim of these clinical studies was to evaluate the safety and efficacy of 2 non-overlapping dose ranges of rivastigmine relative to placebo over a 26-week treatment period in patients with probable AD. MAIN OUTCOME MEASURES AND RESULTS: The results indicate that the average cost savings with high-dose rivastigmine at the end of the trial period are quite low (approximately 29 Pounds per patient; 1997 values), but by extrapolating to a projected lifetime of 3 years, they rise to approximately 1100 Pounds per patient. The largest long term cost savings from treatment are obtained from treating those in the mild category (i.e. MMSE > 20). However, if the time horizon over which savings are estimated is short (i.e. if life expectancy is below 2 years), more costs are saved by prioritising patients with moderate AD (i.e. MMSE between 20 and 11). CONCLUSIONS: The model is a possible approach for estimating cost savings with treatment of AD, given the lack of long term data on resource use and drug efficacy. Caution should be used when extrapolating the results beyond the original study parameters.

Alzheimer Disease↗
PubMed1999

Psychotic symptoms, aggression and restlessness in dementia.

The current article reviews the literature pertaining to psychosis, aggression and restlessness in dementia sufferers examining frequency, course and associations as well as treatment considerations. All of these problems are highly prevalent, with a high impact upon dementia sufferers and their carers. Although there has been an expansion in this literature over the last few years there are still very few studies describing the natural course of behavioural and psychological symptoms in dementia (BPSD) and a paucity of data relating to non-Alzheimer dementias. Several large treatment studies have recently been completed, but there are still very few double blind controlled trials focusing upon BPSD in particular respect to non-pharmacological interventions.

Aged↗
PubMed1998

Craniopharyngioma in children.

PURPOSE: The treatment regimens at presentation and recurrence, the related morbidity, and survival rates were studied for children with craniopharyngioma who were treated at King Faisal Specialist Hospital & Research Center (KFSH&RC). METHODS & MATERIALS: From 1975 to 1996, a total of 56 children younger than 18-years-old at diagnosis underwent treatment with surgery and/or radiotherapy for craniopharyngiomas at KFSH&RC. There was evidence that these patients had advanced disease at diagnosis; 36% of 51 patients whose visual status pretreatment was known were either blind or had major bilateral visual defects prior to treatment, and 36% of the 56 patients had diabetes insipidus. This report concentrates on 44 patients who had first definitive resection at KFSH&RC. Treatment policy was total resection if possible (17 patients), if not, subtotal resection (17 patients) or lesser procedures (10 patients). Five patients received postoperative irradiation after first definitive resection. RESULTS: Ten-year-survival, and progression-free and event-free survival rates were 65%, 39%, and 29%, respectively. There were 9 postoperative deaths; 7 following the first procedure and 2 following resection for relapse, and 3 early deaths at home prior to relapse, following the first resection. None of the 22 patients who underwent less than total resection without postoperative radiation treatment were progression-free at 5 years, whereas the 5 patients who were irradiated remain progression-free. CONCLUSION: A more selective approach to total resection, and the routine use of postoperative irradiation following lesser surgical procedures requires evaluation.

Adolescent↗
PubMed1998

Toll-like receptor-2 mediates lipopolysaccharide-induced cellular signalling.

Vertebrates and invertebrates initiate a series of defence mechanisms following infection by Gram-negative bacteria by sensing the presence of lipopolysaccharide (LPS), a major component of the cell wall of the invading pathogen. In humans, monocytes and macrophages respond to LPS by inducing the expression of cytokines, cell-adhesion proteins, and enzymes involved in the production of small proinflammatory mediators. Under pathophysiological conditions, LPS exposure can lead to an often fatal syndrome known as septic shock. Sensitive responses of myeloid cells to LPS require a plasma protein called LPS-binding protein and the glycosylphosphatidylinositol-anchored membrane protein CD14. However, the mechanism by which the LPS signal is transduced across the plasma membrane remains unknown. Here we show that Toll-like receptor 2 (TLR2) is a signalling receptor that is activated by LPS in a response that depends on LPS-binding protein and is enhanced by CD14. A region in the intracellular domain of TLR2 with homology to a portion of the interleukin (IL)-1 receptor that is implicated in the activation of the IL-1-receptor-associated kinase is required for this response. Our results indicate that TLR2 is a direct mediator of signalling by LPS.

Binding Sites↗
PubMed1998

Randomised controlled trial comparing hospital at home care with inpatient hospital care. I: three month follow up of health outcomes.

OBJECTIVES: To compare hospital at home care with inpatient hospital care in terms of patient outcomes. DESIGN: Randomised controlled trial with three month follow up. SETTING: District general hospital and catchment area of neighbouring community trust. SUBJECTS: Patients recovering from hip replacement (n=86), knee replacement (n=86), and hysterectomy (n=238); elderly medical patients (n=96); and patients with chronic obstructive airways disease (n=32). INTERVENTIONS: Hospital at home care or inpatient hospital care. MAIN OUTCOME MEASURES: Dartmouth COOP chart to measure patients' general health status; SF-36 to measure possible limitations in physical functioning of patients with hysterectomy; disease specific measures-chronic respiratory disease questionnaire, Barthel index for elderly medical patients, Oxford hip score, and Bristol knee score; hospital readmission and mortality data; carer strain index to measure burden on carers; patients' and carers' preferred form of care. RESULTS: At follow up, there were no major differences in outcome between hospital at home care and hospital care for any of the patient groups except that those recovering from hip replacement reported a significantly greater improvement in quality of life with hospital at home care (difference in change from baseline value 0.50, 95% confidence interval 0.13 to 0.88). Hospital at home did not seem suitable for patients recovering from a knee replacement, as 14 (30%) of patients allocated to hospital at home remained in hospital. Patients in all groups preferred hospital at home care except those with chronic obstructive airways disease. No differences were detected for carer burden. Carers of patients recovering from knee replacement preferred hospital at home care, while carers of patients recovering from a hysterectomy preferred hospital care. CONCLUSIONS: Few differences in outcome were detected. Thus, the cost of hospital at home compared with hospital care becomes a primary concern.

Adult↗
PubMed1998

Randomised controlled trial comparing hospital at home care with inpatient hospital care. II: cost minimisation analysis.

OBJECTIVES: To examine the cost of providing hospital at home in place of some forms of inpatient hospital care. DESIGN: Cost minimisation study within a randomised controlled trial. SETTING: District general hospital and catchment area of neighbouring community trust. SUBJECTS: Patients recovering from hip replacement (n=86), knee replacement (n=86), and hysterectomy (n=238); elderly medical patients (n=96); and patients with chronic obstructive airways disease (n=32). INTERVENTIONS: Hospital at home or inpatient hospital care. MAIN OUTCOME MEASURES: Cost of hospital at home scheme to health service, to general practitioners, and to patients and their families compared with hospital care. RESULTS: No difference was detected in total healthcare costs between hospital at home and hospital care for patients recovering from a hip or knee replacement, or elderly medical patients. Hospital at home significantly increased healthcare costs for patients recovering from a hysterectomy (ratio of geometrical means 1.15, 95% confidence interval 1.04 to 1.29, P=0.009) and for those with chronic obstructive airways disease (Mann-Whitney U test, P=0.01). Hospital at home significantly increased general practitioners' costs for elderly medical patients (Mann-Whitney U test, P<0.01) and for those with chronic obstructive airways disease (P=0.02). Patient and carer expenditure made up a small proportion of total costs. CONCLUSION: Hospital at home care did not reduce total healthcare costs for the conditions studied in this trial, and costs were significantly increased for patients recovering from a hysterectomy and those with chronic obstructive airways disease. There was some evidence that costs were shifted to primary care for elderly medical patients and those with chronic obstructive airways disease.

Adult↗
PubMed1998

The use of out of hours health services: a cross sectional survey.

OBJECTIVES: To determine the use and costs of the principal out of hours health services in Buckinghamshire. DESIGN: Prospective cross sectional survey and cost description of patient contacts with out of hours services. SETTING: Buckinghamshire during March and April 1995. SUBJECTS: General practices, accident and emergency departments, ambulance services, and community nursing services. MAIN OUTCOME MEASURE: Contacts with patients and cost of out of hours services. RESULTS: 438 patient contacts/1000 population/year were recorded at an annual incremental cost of between 4.6 m Pounds and 7.2 m Pounds (depending on the costing of general practitioner services), for a population of 660,000. Of these contacts, 21,649 (45%) were with general practitioners. Night time contacts with all services diminished sharply after 10 pm. General practitioners considered that 40% of contacts were unnecessary or could have waited until morning. Over 70% of contacts were for upper respiratory tract infections, earache, gastroenteritis, and other minor ailments. Nursing care was predominantly for elderly people, and 33% of nursing contacts were to supervise medication. Accident and emergency care was predominantely for young adults, especially men, and 41% of attendances were for medical conditions. CONCLUSIONS: New models such as multidisciplinary primary care centres with telephone advice lines and triaging are required to ensure high quality, cost effective care that is responsive to the needs of both consumers and professionals.

Adolescent↗
PubMed1998

Caregivers of children with sexual behavior problems: psychological and familial functioning.

OBJECTIVE: This research examined demographic and functional characteristics of parents of children with sexual behavior problems. METHOD: Families of 72 children with sexual behavior problems completed a structured interview and several psychometric devices at intake into a treatment outcome study. RESULTS: As a group, caregivers manifested signs of a high level of life stress across a wide array of variables, including income, criminal arrest, family violence, sexual abuse, social support, modulation of emotion, and attachment to their child. Foster parents consistently reported significantly lower levels of stress than biological parents. CONCLUSION: Parents and families of children with sexual behavior problems appear multiply entrapped. They are highly distressed and somewhat isolated. The data convincingly demonstrate that in order to maximize the efficacy of treatment for children with sexual behavior problems, parents must be centrally involved and receive services coordinated with those of their child. Group treatment may be advisable to foster formation of a network of peer support for caregivers of children with sexual behavior problems.

Adult↗
PubMed1998

An economic evaluation of vaccination against hepatitis A for frequent travellers.

This paper compares the cost of using inactive Hepatitis A vaccine relative to immunoglobulin as a means of protecting frequent travellers against Hepatitis A. The number of trips to 'at risk' areas is modelled as a Poisson process and results are reported in terms of the discounted gross cost per protected trip over a 10-year period. We find that the expected cost of immunization is lower with immunoglobulin for travellers visiting 'at risk' areas less than five times in 10 years, and lower with Hepatitis A vaccine for those visiting 'at risk' areas more than five times in 10 years.

Cost-Benefit Analysis↗