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Biomedical subjects

S Robinson

Publications and source records attributed to S Robinson.

At least 181 records · Page 10Linked to original sources

Uptake of 99mTc-MDP after uncemented hip arthroplasty: a quantitative analysis of findings around the femoral component in asymptomatic patients.

We studied the pattern of 99mTc-methylene diphosphonate uptake around uncemented femoral components in 44 asymptomatic hip arthroplasties, performing isotope scans at intervals from 4 to 48 months after operation. We used phase-II images obtained with a high-resolution gamma camera and measured the activity in various zones using a specially designed computer program. The components studied at 4, 6, 9 and 12 months were coated with hydroxyapatite (HA) and those studied at 18, 24, 36 and 48 months were not coated. We found a statistically significant fall in activity between four and six months around HA-coated prostheses in all five femoral periprosthetic zones. After six months activity was relatively uniform, but remained higher than that in normal femoral bone at 48 months in non-coated prostheses. We discuss the application of these patterns in the evaluation of painful cementless hip arthroplasties.

Adult↗

Holding children still for procedures.

The attitudes and concerns of 394 paediatric nurses about the practice of restraining children during clinical procedure were surveyed. The majority believed that restraint rather than pain was the most likely cause of distress. Age of the child, degree of urgency and type of procedure were all relevant to the decision whether to hold the child still. Nurses were unsure about the legal position and the majority reported that they had no formal training in holding techniques. These findings indicate the need for more training and guidelines about when to hold children and for the legal position to be clarified.

Adolescent↗

Survey of British clinicians' views on management of patients in persistent vegetative state.

BACKGROUND: The best care and management of patients in persistent vegetative state (PVS) has been the subject of sustained moral and legal debate for a number of years. However, the views of clinicians in the UK involved in caring for patients in PVS are largely unknown. METHODS: A postal questionnaire was sent to 1882 consultant members of the British Association of Orthopaedic Surgeons, the Association of British Neurologists, the Society of British Neurosurgeons, and the British Society of Rehabilitation Medicine. Their views were sought on various aspects of the management and care of PVS, in particular the appropriateness of a decision not to treat and a decision to withdraw artificial nutrition and hydration (ANH). FINDINGS: 1027 doctors responded (55%) of whom 558 (54%) had experience of managing patients in PVS. Over 90% of responding doctors considered that it could be appropriate not to treat acute infections and other life-threatening conditions. 65% of doctors considered that withdrawal of ANH could be appropriate. About two-thirds of doctors who thought treatment-limiting decisions could be appropriate thought that such decisions could be considered with the first 12 months of the patient being in PVS. Despite recent case law, less than half the doctors responding to the survey thought that an advance directive made by the patient should have a decisive influence in determining treatment-limiting decisions. Most doctors would like decisions about withdrawing ANH to be made in conjunction with family members and in accordance with agreed guidelines but without the need to go to court. INTERPRETATION: There is a broad consensus among doctors that treatment-limiting decisions are sometimes appropriate for patients in PVS, irrespective of whether they have experience of the condition or of the specialty to which they belong. However, two thirds of doctors said that such decisions can be considered at a time earlier than that recommended by the British Medical Association. It is not clear why some doctors thought a decision not to treat could be appropriate while a decision to withdraw ANH would not be.

Advance Directives↗

Rapid, solid phase extraction technique for the high-throughput assay of darifenacin in human plasma.

A novel method has been developed for the rapid solid phase extraction of drugs and metabolites from biological fluids, prior to further analysis. The newly designed, 96-tube micropreparation block facilitates high throughput by enabling the extraction of 96 samples simultaneously. The system is described, linked to HPLC/APCI-MS/MS, for the determination of darifenacin in human plasma. The resulting procedure, using deuterated darifenacin as internal standard, is validated over the concentration range 25-2000 pg/mliter; accuracy (0.6-4.6%) and precision (3.6-18.8%) are considered acceptable and overall recovery was determined to be approximately 50%.

Benzofurans↗

Maternal nutrition in early and late pregnancy in relation to placental and fetal growth.

OBJECTIVE: To assess how nutrient intakes of mothers in early and late pregnancy influence placental and fetal growth. DESIGN: Prospective observational study. SETTING: Princess Anne Maternity Hospital, Southampton. SUBJECTS: 538 mothers who delivered at term. MAIN OUTCOME MEASURES: Placental and birth weights adjusted for the infant's sex and duration of gestation. RESULTS: Mothers who had high carbohydrate intakes in early pregnancy had babies with lower placental and birth weights. Low maternal intakes of dairy and meat protein in late pregnancy were also associated with lower placental and birth weights. Placental weight fell by 49 g(95% confidence interval 16 g to 81 g; P=0.002) for each log g increase in intake of carbohydrate in early pregnancy and by 1.4 g (0.4 g to 2.4 g; P=0.005) for each g decrease in intake of dairy protein in late pregnancy. Birth weight fell by 165 g (49 g to 282 g; P=0.005) for each log g increase in carbohydrate intake in early pregnancy and by 3.1 g (0.3 g to 6.0 g; P=0.03) for each g decrease in meat protein intake in late pregnancy. These associations were independent of the mother's height and body mass index and of strong relations between the mother's birth weight and the placental and birth weights of her offspring. CONCLUSION: These findings suggest that a high carbohydrate intake in early pregnancy suppresses placental growth, especially if combined with a low dairy protein intake in late pregnancy. Such an effect could have long term consequences for the offspring's risk of cardiovascular disease.

Adolescent↗

Nutrition in pregnancy and the concentrations of proinsulin, 32-33 split proinsulin, insulin, and C-peptide in cord plasma.

As insulin is a major fetal growth hormone, we have related the mother's nutrient intakes (assessed by a food frequency questionnaire) and other influences associated with fetal growth to the baby's concentrations of insulin and its propeptides in umbilical cord plasma. Among 391 term babies studied, those whose mothers had high energy intakes in early pregnancy and low protein intakes in late pregnancy had lower cord plasma concentrations of 32-33 split proinsulin, insulin, and C-peptide. Concentrations of split proinsulin fell by 0.66 (95% Cl 0.29 to 1.03, p = 0.0006) log pmol l-1 for each log kcal increase in the mother's energy intake in early pregnancy and by 0.005 (95% Cl 0.000 to 0.010, p = 0.04) log pmol l-1 for each g decrease in protein intake in late pregnancy. Insulin and propeptide concentrations were however unrelated to the mother's height and body mass index, and to smoking during pregnancy. These observations parallel recent studies relating the same pattern of dietary intakes to impaired fetal and placental growth. Although dietary intakes assessed by food frequency questionnaires allow only cautious conclusions, our findings could have implications for the offspring's risk of Type 2 diabetes mellitus in adult life.

Adolescent↗

Environmental enhancement of growth factor-mediated oligodendrocyte precursor proliferation.

The timing of oligodendrogenesis depends on the specific location within the central nervous system, suggesting the local environment influences oligodendrocyte precursor proliferation. Spinal cord and optic nerve oligodendrocyte precursors both proliferate in response to platelet-derived growth factor (PDGF). Here we show that neurotrophin-3 (NT-3) enhanced PDGF-induced proliferation of optic nerve oligodendrocyte precursors, and these cells were labeled by an anti-trkC antibody. By contrast, NT-3 did not enhance PDGF-induced proliferation of spinal cord oligodendrocyte precursors, and these cells were not labeled by an anti-trkC antibody. Furthermore, PDGF-induced oligodendrocyte precursor proliferation was greater in spinal cord than in optic nerve cultures. The difference in NT-3 response between spinal cord and optic nerve oligodendrocyte precursors appears cell intrinsic, while the enhanced PDGF-induced proliferation of spinal cord oligodendrocyte precursors appears environmentally regulated. The spinal cord PDGF proliferation-enhancing activity may provide a mechanism to allow temporal and spatial regulation of gliogenesis.

Animals↗

The role of TGF-beta in patterning and growth of the mammary ductal tree.

Evidence that transforming growth factor beta (TGF-beta) influences pattern formation in the developing mammary gland and negatively regulates ductal growth is reviewed. In the mouse, overexpression of TGF-beta transgenes during puberty reduces the rate of growth of the ductal tree and simplifies the pattern of arborization, while expression during pregnancy also interferes with lactation. Expression studies in the normal mouse gland indicate that TGF-beta is synthesized in the mammary epithelium, with the three isoforms showing somewhat different spatial and temporal distributions. Exogenous TGF-beta applied directly to the gland in situ inhibits epithelial cell division within hours, and strongly stimulates extracellular matrix synthesis over a longer time course. Normal human breast cells as well as certain breast cancer cell lines also secrete TGF-beta and are themselves inhibited by it, suggesting an autoregulatory feedback circuit, that in some cases appears to be modulated by estradiol. Taken together, the evidence suggests a model in which growth and patterning of the mammary ductal tree are regulated, at least in part, by TGF-beta operating through an autocrine feedback mechanism and by paracrine circuits associated with epithelial-stromal interactions.

Animals↗

Dyslipidaemia is associated with insulin resistance in women with polycystic ovaries.

OBJECTIVE: Polycystic ovary syndrome (PCOS) is characterized by hyperinsulinaemia and insulin resistance. Previous reports of lipid abnormalities in the syndrome have produced conflicting results which may, in part, be related to the lack of appropriate controls for the obese women with PCOS. Only one study has related lipid levels to insulin sensitivity. The objective of this study was to assess lipids and lipoproteins in women with PCOS, to compare the results with weight matched controls, and to relate the findings to indices of insulin secretion and action, and to menstrual history. DESIGN: A cross-sectional study of insulin sensitivity and lipids in a cohort of PCO subjects compared to weight and ethnic group matched controls. PATIENTS AND METHODS: We have therefore investigated glucose tolerance, plasma lipids and lipoproteins in 19 lean (LP) and 55 obese (OP) patients with PCO and compared the results with those in 22 lean (LC) and 15 obese (OC) control women. Insulin sensitivity was measured in the same subjects with a short insulin (0.05 U/kg i.v. insulin) tolerance test (LP, n = 18; OP, n = 20; LC, n = 19; OC, n = 11). RESULTS: Results are expressed as mean +/- SEM or median (interquartile range). Fasting plasma glucose levels were similar in the four groups but the plasma glucose area was higher after oral glucose (75 g) in both the lean and obese PCOS groups than in their controls (LC 32.4 +/- 0.7 vs LP 35.2 +/- 1.2, P < 0.01; OC 34.7 +/- 1.8 vs OP 37.8 +/- 1.5 mmol/l/3 h, P < 0.01). Insulin sensitivity was significantly reduced in obese PCOS women (LC 196 +/- 9 vs LP 179 +/- 9, NS; OC 168 +/- 12 vs OP 133 +/- 9 mmol/l/min, P < 0.01). Total serum cholesterol levels were similar in the four groups but HDL2-cholesterol was reduced in both obese and lean PCOS (LC 0.42 (0.38-0.62), LP 0.31 (0.26-0.44), P < 0.05; OC 0.34 (0.21-0.47), OP 0.21 (0.12-0.32) mmol/l, P < 0.01). Total HDL-cholesterol was decreased significantly only in the obese PCOS group. Body mass index correlated significantly and negatively with total HDL-cholesterol and with HDL2-cholesterol levels both within the PCOS group and the control women. Using multiple regression insulin insensitivity contributes significantly beyond BMI to the low HDL-cholesterol in women with polycystic ovaries. CONCLUSION: Polycystic ovary syndrome is associated with biochemical risk factors for premature vascular disease, which cannot be explained by obesity alone.

Adult↗

Audit in the therapy professions: some constraints on progress.

AIMS: To ascertain views about constraints on the progress of audit experienced by members of four of the therapy professions: physiotherapy, occupational therapy, speech and language therapy, and clinical psychology. METHODS: Interviews in six health service sites with a history of audit in these professions. 62 interviews were held with members of the four professions and 60 with other personnel with relevant involvement. Five main themes emerged as the constraints on progress: resources; expertise; relations between groups; organisational structures; and overall planning of audit activities. RESULTS: Concerns about resources focused on lack of time, insufficient finance, and lack of access to appropriate systems of information technology. Insufficient expertise was identified as a major constraint on progress. Guidance on designing instruments for collection of data was the main concern, but help with writing proposals, specifying and keeping to objectives, analysing data, and writing reports was also required. Although sources of guidance were sometimes available, more commonly this was not the case. Several aspects of relations between groups were reported as constraining the progress of audit. These included support and commitment, choice of audit topics, conflicts between staff, willingness to participate and change practice, and concerns about confidentiality. Organisational structures which constrained audit included weak links between heads of professional services and managers of provider units, the inhibiting effect of change, the weakening of professional coherence when therapists were split across directorates, and the ethos of regarding audit findings as business secrets. Lack of an overall plan for audit meant that while some resources were available, others equally necessary for successful completion of projects were not. CONCLUSION: Members of four of the therapy professions identified a wide range of constraints on the progress of audit. If their commitment to audit is to be maintained these constraints require resolution. It is suggested that such expert advice, but also that these are directed towards the particular needs of the four professions. Moreover, a forum is required within which all those with a stake in therapy audit can acknowledge and resolve the different agendas which they may have in the enterprise.

Allied Health Occupations↗

Adding a vocational focus to mental health rehabilitation.

OBJECTIVES: The study examined the effect of adding two employment specialists to the staff of a community mental health center; their sole responsibility was to develop the skills and positive work attitudes that clients with severe mental illness need to enter the state vocational rehabilitation system or to seek employment. METHODS: A total of 122 clients were randomly assigned to a program with an employment specialist or to a control group with no specialized vocational services. Clients in the program were taught work skills and attitudes in group and individual sessions and through a trial work experience. A schedule of rewards reinforced positive changes. Outcomes measured were skill gains, changes in work attitudes, attainment of employment, and entry into the state vocational rehabilitation system. RESULTS: At nine months, 34 of the 61 clients in the program achieved positive changes in vocational status that included competitive employment, participation in training and evaluation programs operated by the state vocational system, and formal referral to the system. Only one client in the control group was linked to the state system. Skill gains and positive changes in work attitudes were found for all program clients. Logistical regression suggested that program participation, rather than client characteristics, was an important predictor of a positive outcome. CONCLUSIONS: Over a relatively short time period, targeted vocational programs can help clients with severe mental illness develop the skills and attitudes necessary to attain employment or entry into the vocational rehabilitation system. Vocational rehabilitation can be an integral part of the rehabilitation process for all mental health clients.

Activities of Daily Living↗

Nutrition, insulin and polycystic ovary syndrome.

The adverse effects of obesity on reproductive function in women are well recognized, but women with polycystic ovary syndrome (PCOS), the most common cause of anovulatory infertility, seem particularly vulnerable to the effects of excessive intake of calories. Polycystic ovary syndrome is associated with hyperinsulinaemia and insulin resistance, the causes of which remain unclear. These metabolic abnormalities are, in turn, related to a disorder of energy expenditure, characterized by reduced post-prandial thermogenesis. It is proposed that these closely interlinked phenomena that, particularly in overweight subjects, are associated with anovulation, may confer a biological advantage for women with PCOS at times of food deprivation, when such women may reproduce more successfully than those without PCOS. A possible causal link between hyperinsulinaemia and ovulation is explored by reference to the interaction of insulin and LH in granulosa cells.

Energy Intake↗