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Biomedical subjects

P Dolan

Publications and source records attributed to P Dolan.

At least 37 records · Page 2Linked to original sources

Conceptually new sulfone analogues of the hormone 1alpha, 25-dihydroxyvitamin D(3): synthesis and preliminary biological evaluation.

A conceptually new series of vitamin D(3)-like nonfluorinated and fluorinated 16-ene side chain tert-butyl sulfones 3-7 has been synthesized. Even though these novel C,D-ring side chain analogues of the hormone 1alpha,25-dihydroxyvitamin D(3) (1,1,25D(3)) lack a terminal OH group, thought previously to be essential for high biological activity, they are highly antiproliferative and, in several cases, transcriptionally active in vitro but desirably noncalcemic in vivo. The side chain sulfone group may be binding to the nVDR as a hydrogen-bond acceptor, in contrast to the hydrogen-bond donor function of the 25-OH group of natural 1,25D(3).

Animals↗

Effect of discussion and deliberation on the public's views of priority setting in health care: focus group study.

OBJECTIVE: To investigate the extent to which people change their views about priority setting in health care as a result of discussion and deliberation. DESIGN: A random sample of patients from two urban general practices was invited to attend two focus group meetings, a fortnight apart. SETTING: North Yorkshire Health Authority. SUBJECTS: 60 randomly chosen patients meeting in 10 groups of five to seven people. MAIN OUTCOME MEASURES: Differences between people's views at the start of the first meeting and at the end of the second meeting, after they have had an opportunity for discussion and deliberation, measured by questionnaires at the start of the first meeting and the end of the second meeting. RESULTS: Respondents became more reticent about the role that their views should play in determining priorities and more sympathetic to the role that healthcare managers play. About a half of respondents initially wanted to give lower priority to smokers, heavy drinkers, and illegal drug users, but after discussion many no longer wished to discriminate against these people. CONCLUSION: The public's views about setting priorities in health care are systematically different when they have been given an opportunity to discuss the issues. If the considered opinions of the general public are required, surveys that do not allow respondents time or opportunity for reflection may be of doubtful value.

Adolescent↗

Dynamic forces acting on the lumbar spine during manual handling. Can they be estimated using electromyographic techniques alone?

STUDY DESIGN: Compressive loading of the lumbar spine was analyzed using electromyographic, movement analysis, and force-plate techniques. OBJECTIVES: To evaluate the inertial forces that cannot be detected by electromyographic techniques alone. SUMMARY OF BACKGROUND DATA: Links between back pain and manual labor have stimulated attempts to measure spine compressive loading. However, direct measurements of intradiscal pressure are too invasive, and force plates too cumbersome for use in the workplace. Electromyographic techniques are noninvasive and portable, but ignore certain inertial forces. METHODS: Eight men lifted boxes weighing 6.7 and 15.7 kg from the ground, while joint moments acting about L5-S1 were quantified 1) by using a linked-segment model to analyze data from Kistler force plates and a Vicon movement-analysis system, and 2) by measuring the electromyographic activity of the erector spinae muscles, correcting it for contraction speed and comparing it to moment generation during static contractions. The linked-segment model was used to calculate the "axial thrust," defined as the component of the L5-S1 reaction force that acts along the axis of the spine and that is unrelated to trunk muscle activity or static body weight. RESULTS: Peak extensor moments predicted by the two techniques were similar and equivalent to spinal compressive forces of 2.9-4.8 kN. The axial thrust "hidden" from the electromyographic technique was negligible during slow lifts, and remained below 4% of peak spinal compression even during fast heavy lifts. Peak axial thrust was proportional to the peak vertical ground reaction (R2 = 0.74). CONCLUSIONS: Electromyographic techniques can measure dynamic spinal loading, but additional force-plate data would improve accuracy slightly during lifts requiring a vigorous upward thrust from the legs.

Adult↗

Health-related quality of life of Colles' fracture patients.

Recent guidelines published by the National Osteoporosis Foundation (NOF) make extensive use of quality-adjusted life-years (QALYs). Crucial to these guidelines, therefore, are the assumptions that are made about the health-related quality of life (HRQoL) gained from the avoidance of osteoporotic fractures. This paper reports on a study in which 50 Colles' fracture patients were asked to describe their health at each visit during treatment using the EuroQol descriptive system and to value their own health using the visual analogue scale (VAS). By applying a set of population-derived valuations to the states reported by the patients, the QALY loss is shown to be about 2%. This is about half of the loss, based upon clinician judgement, that is contained in the NOF guidelines. In addition, the results suggest that it may be possible to use VAS scores to predict treatment requirements, since those patients who require fewer visits have, on average, higher initial VAS scores.

Aged↗

Public views on health care rationing: a group discussion study.

This small-scale study develops a new methodology for investigating which ethical principles of health care rationing the public support after discussion and deliberation. In ten groups of about six people, members of the public are asked to discuss a hypothetical rationing choice, concerning four identified patients who are described in general terms but without detailed information. It is explained to respondents that the purpose of the exercise is to find out what general ethical principles they support. Discussions are chaired by an academic specialising in health policy, whose role is to encourage debate but not actively to participate. On the basis of an innovative qualitative data analysis, which translates what people say into ethical principles identified in the theoretical literature, the public appear to support three main rationing principles: (1) a broad 'rule of rescue' that gives priority to those in immediate need, (2) health maximisation and (3) equalisation of lifetime health. To our knowledge, this pluralistic viewpoint on rationing has never been developed into a coherent theoretical position, nor into a quantifiable model that health care managers can use for guidance.

Adult↗

Experimental determination of stress distributions in articular cartilage before and after sustained loading.

OBJECTIVE: To test the hypotheses that stress concentrations exist within articular cartilage, and are intensified by sustained 'creep' loading. DESIGN: Matched-pair comparison of stress distributions in cartilage, in vitro, before and after creep. BACKGROUND: The ability of cartilage to equalize contact stresses between articulating surfaces may be compromised by undulations in the subchondral bone, and by variations in chemical composition. Furthermore, any stress concentrations within cartilage may be affected by creep loading, which-reduces its water content. METHODS: Sixteen specimens of apparently normal cartilage-on-bone, 12 mm x 15 mm, were removed from the femoral condyles and tibial plateaux of patients undergoing total knee replacement. The cartilage was subjected to a nominal compressive stress of 2 MPa by means of a 10 mm-diameter flat impermeable indentor. During the 20 s loading period, a miniature pressure transducer, side-mounted in a 0.9 mm-diameter needle, was pulled through the cartilage in a direction parallel to the surface, while transducer output and position were sampled at 25 Hz. 'Stress profiles' were obtained with the transducer pointing in the 12 o'clock and 3 o'clock directions, and were repeated after creep loading at 1.6 MPa for 2 h. RESULTS: Validation tests indicated that transducer output was proportional to the average compressive stress, but overestimated it by 9-15%. Stresses were greatest under the centre of the indentor, and showed local variations ('concentrations') which were increased in number and size after creep loading. CONCLUSIONS: Measured values of compressive stress incorporate small systematic errors. Nevertheless, the results presented clearly support both hypotheses.

Aged↗

Good outcome from surgery for ampullary tumour.

BACKGROUND: Ampulla of Vater tumours are rare but usually resectable. There is debate as to the better surgical approach between the standard radical procedure, which provides adequate resection margins, and local resection, which may carry a lower mortality. This study reports the 16-year experience of a specialist unit with these tumours, and compares our results with that of recently published series. METHOD: A retrospective review of patients admitted with an ampullary tumour to the Hepatobiliary and Pancreatic Surgery Unit, Royal Adelaide Hospital, Adelaide, Australia, between January 1981 and April 1997. RESULTS: Twenty-five patients (13 men, 12 women) of median age 65 years were admitted with an ampullary tumour to the unit during this period. The most common presentation was obstructive jaundice. Multiple endoscopic biopsy was found to be very reliable in distinguishing between benign and malignant tumours. Five patients, all male, had benign neoplasms: three adenomas, one carcinoid and one gangliocytic paraganglioma. Transduodenal local excision was performed in four patients. One patient had a Whipple procedure resulting in the only in-hospital death at 3 months. Twenty patients had adenocarcinoma, of which 13 patients had a pancreaticoduodenectomy, two local excisions, two palliative bypasses, two were unfit for surgery and one declined surgery. The resectability rate was 88%, with no operative mortalities. The 5-year actuarial survival of patients who underwent radical resection was 49%. CONCLUSIONS: Proximal pancreaticoduodenectomy, preferably a pylorus-preserving procedure, is safe and effective in the treatment of ampullary carcinoma, with low operative mortality and good long-term survival. Local resection is only recommended for small benign tumours and for patients who may be unfit for radical surgery.

Adult↗

Costs of breast cancer treatment in the United Kingdom.

Breast cancer is a major source of mortality and morbidity to women in the UK. In this paper we estimate the costs of treating breast cancer using random samples of secondary and primary care records. We estimate the average cost per case of breast cancer to be pound 7247 which gives a total cost of pound 243 million per annum for the whole of the UK.

Journal Article↗

Prediction of maximal back muscle strength from indices of body mass and fat-free body mass.

OBJECTIVES: The purpose of this study was to examine, in healthy volunteers, the relationship between back extensor muscle strength and body size. METHODS: The maximal voluntary isometric back extensor strength of 456 volunteers, aged 18-42 yr and with no history of low back pain, was measured in a standing, slightly flexed forward posture. This was then correlated with two indices of body size: body mass and fat-free body mass. RESULTS: Significant linear relationships were observed between back muscle strength and each of the two indices of body size. There was a gender difference in both the slope and the intercept of the regression equations describing the relationships. There was no independent influence of age within the range studied. CONCLUSION: It was possible to establish predictive equations for back extensor strength based on body size which could be used to quantify strength 'deficits', for instance in patients with low back pain, and to prescribe submaximal target forces for use in endurance training and testing.

Adult↗

Valuing health-related quality of life. Issues and controversies.

An important consideration when establishing priorities in healthcare is the likely effect that alternative allocations will have on the health-related quality of life (HR-QOL) of the relevant population. This paper considers some of the important issues and controversies surrounding the valuation of HR-QOL. It considers the theoretical and empirical evidence regarding 3 crucial questions: (i) what is to be valued?; (ii) how is it to be valued?; and (iii) who is to value it? Many important yet unresolved issues emerge and directions for future research are suggested. It is argued that this research agenda should have the gathering and analysis of qualitative data at its forefront.

Delivery of Health Care↗

Noncalcemic, antiproliferative, transcriptionally active, 24-fluorinated hybrid analogues of the hormone 1alpha, 25-dihydroxyvitamin D3. Synthesis and preliminary biological evaluation.

Four new hybrid analogues of 1alpha,25-dihydroxyvitamin D3 (1) have been synthesized in a convergent manner by joining A-ring and C, D-ring fragments. Each hybrid analogue, having a noncalcemic 1-hydroxymethyl group and a potentiating 16-ene 24,24-difluorinated C,D-ring side chain, was designed to be lipophilic and inert toward 24-hydroxylase enzyme catabolism. Each hybrid analogue with 1beta, 3alpha-substituent stereochemistry (i.e., analogues 3b and 4b) showed a pharmacologically desirable combination of in vitro high antiproliferative activity in two different cell lines and high transcriptional activity with also low calcemic activity in vivo.

Administration, Oral↗

Variations in population health status: results from a United Kingdom national questionnaire survey.

OBJECTIVE: To measure the health of a representative sample of the population of the United Kingdom by using the EuroQoL EQ-5D questionnaire. DESIGN: Stratified random sample representative of the general population aged 18 and over and living in the community. SETTING: United Kingdom. SUBJECTS: 3395 people resident in the United Kingdom. MAIN OUTCOME MEASURES: Average values for mobility, self care, usual activities, pain or discomfort, and anxiety or depression. RESULTS: One in three respondents reported problems with pain or discomfort. There were differences in the perception of health according to the respondent's age, social class, education, housing tenure, economic position, and smoking behaviour. CONCLUSIONS: The EQ-5D questionnaire is a practical way of measuring the health of a population and of detecting differences in subgroups of the population.

Adolescent↗

Regional assessment of joint position sense in the spine.

STUDY DESIGN: A test-retest design was used to assess the reproducibility of position sense measurements of the spine recorded at T1, T7, L1, and S2. OBJECTIVES: To measure position sense at four spinal levels in healthy volunteers and to determine if this varies on a day-to-day basis. The overall purpose is to provide baseline data for studying position sense of the spine in patients with spinal lesions. SUMMARY OF BACKGROUND DATA: Position sense, which is one component of proprioception, is assessed by the ability to reposition the body after displacement. In peripheral joints, position sense is accurate to within a few degrees. Studies on the spine suggest similar accuracy, but most have used indirect methods of measurement that often incorporate unusual extraneous cues. METHODS: Spinal position sense was assessed in 20 healthy volunteers using an electromagnetic movement sensor system, the 3-Space Fastrak (Polhemus, Colchester, VT), to measure absolute error in actively reproducing upright and flexed positions during movements in both coronal and sagittal planes. Three randomized measurements were taken for each position in one testing session, and measurements were repeated in all participants 2 weeks later. RESULTS: Same-day measurements indicate that spinal position sense is reproducible in upright postures to within a mean of 3.79 +/- 2.56 for movements in the sagittal plane and 2.26 +/- 1.59 degrees for movements in the coronal plane. Corresponding measurements for flexed postures are 5.27 degrees +/- 3.47 degrees and 3.70 +/- 2.62 degrees, respectively. Intraclass correlation coefficients between repeated measurements are generally good in the sagittal plane but are affected by side dominance in the coronal plane. Also, repositioning errors tend to increase on ascending the spine. Repeat measurements taken 2 weeks later show similar values. CONCLUSIONS: 1) Healthy volunteers were able to reposition their spine with considerable accuracy as measured with the 3-Space Fastrak; 2) this ability does not change significantly on a day-to-day basis; and 3) the 3-Space Fastrak offers a noninvasive and accurate method for the measurement of spinal position sense.

Adult↗

Conversion of pancreas allograft rejection to acceptance by liver transplantation.

BACKGROUND: Liver allografts of PVG(RT1c)-->DA(RT1a) are spontaneously accepted, whereas pancreas, heart, and kidney allografts are rejected. Our previous studies have shown that simultaneous liver and pancreas transplantation prevents pancreas allograft rejection. The aim of this study was to examine the effect of liver transplantation on subsequent pancreas allografts and on ongoing pancreas rejection. METHODS: Heterotopic, duct-ligated segmental pancreas grafts were transplanted into streptozotocin-induced diabetic recipients (60 mg/kg body weight i.p.) with or without orthotopic liver grafting at different times. Experimental design was as follows. Group 1 received PVG-->PVG pancreas syngrafts (n=6); group 2, PVG-->DA pancreas allografts (n=7); groups 3-5, PVG-->DA pancreas allografts followed by liver transplantation on day 2 (n=6), on day 4 (n=5), and on day 6 (n=5), respectively, group 6, PVG-->DA pancreas allografts after liver transplantation at 4 weeks (n=6). RESULTS: The results showed that pancreas allografts in group 2 were rejected from postoperative day 7 to 13. Liver transplantation prevented subsequent pancreas allograft rejection in group 6. Ongoing pancreas rejection was reversed by liver transplantation with subsequent graft acceptance in groups 3-5. Significant graft-infiltrating lymphocyte apoptosis was demonstrated at 2 weeks in pancreas transplants associated with liver grafting. Graft-versus-host disease was not detected in the pancreas recipients. CONCLUSIONS: We conclude that pancreas allografts in the PVG-->DA combination are rejected rapidly with median survival time of 9 days. Liver transplantation can protect subsequent pancreas grafts from rejection and reverse ongoing pancreas graft rejection with subsequent pancreatic acceptance. Graft-infiltrating lymphocyte apoptosis may be associated with the process of graft acceptance.

Animals↗

Using the person trade-off approach to examine differences between individual and social values.

Health state valuations, elicited by methods such as the standard gamble and the time trade-off, give an indication of the value that an individual attaches to particular health states. As measures of individual values, it has been argued that such valuations serve as poor proxies for social preferences, which, it is suggested, are a function of other factors, such as the initial severity of the patient's health state. The person trade-off (PTO) method has been proposed as a technique which takes account of many of these other factors. This paper reports on a study using the PTO to investigate whether an individual's preferences over treatments for themselves differ from their preferences when they are asked to think about the treatment of other people. The results suggest that there is indeed a difference, although qualitative data suggests that health gain is an important determinant of social value. This latter finding runs counter to those of a number of other studies which suggest that concerns about pre-treatment severity are as, if not more, important. Possible explanations for the differences are put forward.

Adult↗