Atypical prion protein in sheep brain collected during the British scrapie-surveillance programme

Scrapie of sheep and goats is the most common prion disease (or transmissible spongiform encephalopathy, TSE) of mammals and aggregates of abnormal, proteinase-resistant prion protein (PrPSc) are found in all naturally occurring prion diseases. During active surveillance of British sheep for TSEs, 29 201 sheep brain stem samples were collected from abattoirs and analysed for the presence of PrPSc. Of these samples, 54 were found to be positive by using an ELISA screening test, but 28 of these could not be confirmed initially by immunohistochemistry. These unconfirmed or atypical cases were generally found in PrP genotypes normally associated with relative resistance to clinical scrapie and further biochemical analysis revealed that they contained forms of PrPSc with a relatively protease-sensitive amyloid core, some resembling those of Nor98 scrapie. The presence of these atypical forms of protease-resistant PrP raises concerns that some TSE disorders of PrP metabolism previously may have escaped identification in the British sheep population.

Estimation of the relative risk of developing clinical scrapie: the role of prion protein (PrP) genotype and selection bias

Prion protein (PrP) genotype data from statutory confirmed cases and from three non-case datasets have been used to calculate the odds ratio (or) for the development of clinical scrapie for an individual sheep of a given PrP genotype, compared with one possessing the "wild-type" ARQ/ARQ genotype. Logistic regression has been used to estimate the ors, and a multiple-test procedure has been used to evaluate the statistical significance of each comparison. The results are similar to those observed in other studies: the VRQ/VRQ genotype has or point estimates greater than 20; the ARQ/VRQ and ARH/VRQ genotypes have or point estimates between 5 and 20; AHQ/VRQ between 0.03 and 0.1; ARR/VRQ 0.4 and 0.5; all the other PrP genotypes, excluding ARR/ARR, ARR/ARH and AHQ/ARH for which no clinical cases have been recorded have or point estimates of less than 0.3. The estimates derived from each dataset are comparable, but not identical. This can be explained by plausible biases inherent in the sampling of the non-case populations.

Serous carcinoma arising in an adenofibroma of the endometrium

A serous carcinoma and endometrial intraepithelial carcinoma were encountered in an endometrial adenofibroma in a 61-year-old woman. The carcinoma involved the myometrium and cervix (stage IIa). To our knowledge, this is the third documented case of an adenocarcinoma and the first serous carcinoma involving a uterine adenofibroma.

N-t-Butyl hydroxylamine is an antioxidant that reverses age-related changes in mitochondria in vivo and in vitro

N-t-butyl hydroxylamine (NtBHA) delays senescence-dependent changes in human lung fibroblasts (IMR90) (Atamna et al., J. Biol. Chem. 275, 6741-6748). The current study examines the effect of NtBHA on mitochondria in old and young rats and human primary fibroblasts (IMR90). In NtBHA-treated rats, the age-dependent decline in food consumption and ambulatory activity was reversed without affecting body weight. The respiratory control ratio of mitochondria from liver of old rats improved after feeding NtBHA. These findings suggest that NtBHA improved mitochondrial function in vivo. The age-dependent increase in proteins with thiol-mixed disulfides was significantly lower in old rats treated with NtBHA. NtBHA was effective only in old rats; no significant effect was observed in young rats. In IMR90 cells, NtBHA delayed senescence-associated changes in mitochondria and cellular senescence induced by maintaining the cells under suboptimal levels of growth factors. Proteasomal activity was also higher in cells treated with NtBHA than in untreated cells. NtBHA accumulates in cells 10- to 15-fold the extracellular concentration and is maintained by mitochondrial NADH. NtBHA is an antioxidant that is recycled by mitochondrial electron transport chain and prevents radical-induced toxicity to mitochondria.

How are policy makers using evidence? Models of research utilisation and local NHS policy making

STUDY OBJECTIVE

This paper is based on a qualitative study that aimed to identify factors that facilitate or impede evidence-based policy making at a local level in the UK National Health Service (NHS). It considers how models of research utilisation drawn from the social sciences map onto empirical evidence from this study.

DESIGN

A literature review and case studies of social research projects that were initiated by NHS health authority managers or GP fundholders in one region of the NHS. In depth interviews and document analysis were used.

SETTING

One NHS region in England.

PARTICIPANTS

Policy makers, GPs and researchers working on each of the social research projects selected as case studies.

MAIN RESULTS

The direct influence of research evidence on decision making was tempered by factors such as financial constraints, shifting timescales and decision makers' own experiential knowledge. Research was more likely to impact on policy in indirect ways, including shaping policy debate and mediating dialogue between service providers and users.

CONCLUSIONS

The study highlights the role of sustained dialogue between researchers and the users of research in improving the utilisation of research-based evidence in the policy process.

Practical and theoretical issues in gene-targeting studies and their application to behaviour

Some of the major practical and theoretical issues that are associated with gene-targeting studies in mice are discussed. The availability of sufficient space to house the extensive breeding colonies associated with studies in gene-manipulated mice is an important logistical consideration that requires consideration at an early stage. A practical example is discussed which illustrates some of these issues. Problems associated with disease control and methods of maintaining the health status of valuable colonies are also outlined. Differences in the behavioural phenotype of inbred mouse strains pose important issues for study design and selection of host mouse lines. The results from studies exploring variations in the behavioural phenotype of six common inbred strains are briefly outlined. The impact of phenotypic variation on behavioural studies is considered and the implications for experimental design are discussed.

The role of fine needle aspiration cytology (FNAC) in the investigation of superficial lymphadenopathy; uses and limitations of the technique

Aspirates (n = 163) from 157 patients with enlarged superficial lymph nodes were obtained over a 5-year period in a combined surgical/FNAC clinic. A definitive diagnosis was achieved in over 77% of the cases: benign 52.7%, malignant 25.1%. The diagnostic accuracy was 94.4%, sensitivity 85.4%, and specificity 100%. The false-negative rate was 12.5% but decreased to 3.5% when lymphoma cases were excluded. There were 36 cases of metastatic disease, the majority of which were from a primary breast carcinoma. The main diagnostic difficulty was in distinguishing low-grade lymphoma from reactive hyperplasia. An added advantage was that aspirated material could be used in ancillary tests to help with the differential diagnosis. FNAC has a well-defined role in the investigation of superficial lymphadenopathy. Used in the proper setting it will provide a definitive diagnosis in the majority of cases, especially relating to recurrent malignancy or metastatic disease. Patients with a reactive cytological picture and no clinically suspicious symptoms could be spared unnecessary surgery and reviewed through follow up. This technique is cost-effective, of high diagnostic accuracy, and results in considerable resource savings.

Evidence-based policy-making in the NHS: exploring the interface between research and the commissioning process

BACKGROUND

The UK National Health Service (NHS) R&D strategy acknowledges the importance of developing an NHS where practice and policy is more evidence-based. This paper is based on a qualitative study which aimed to identify factors which facilitate or impede evidence-based policy-making at a local level in the NHS.

METHODS

The study involved a literature review and case studies of social research projects which were initiated by NHS health authority managers or general practitioner (GP) fundholders in one region of the NHS. Data were collected through in-depth interviews with lead policy-makers, GPs and researchers working on each of the case studies and analysis of project documentation.

RESULTS

An over-arching theme from the analysis was that of the complexity of R&D in purchasing. The two worlds of research and health services management often sit uncomfortably together. For this reason it was not possible to describe a 'blueprint' for successful R&D, although several important issues emerged. These include sharing an appropriate model for research utilization, the importance of relationships in shaping R&D, the importance of influence and commitment in facilitating evidence-based change, and the resourcing of R&D in purchasing.

CONCLUSIONS

These issues have important implications for the strategic development of R&D as well as for individual project application. Moving beyond the rhetoric of evidence-based policy-making is more likely if both policy-makers and researchers openly acknowledge this complexity and give due concern to the issues outlined.

Use of formal and informal care among people with prolonged fatigue: a review of the literature

Prolonged fatigue is a common symptom in the community and a common complaint in GPs' surgeries. The current consensus is that prolonged fatigue is most appropriately managed within primary care but that quality of care is patchy. Diagnosis is difficult and there is no conclusive evidence about effective treatment. This can lead to confusion and controversy among lay people and health professionals alike. Although the value of a positive doctor-patient relationship is emphasized, general practice consultations are frequently experienced as difficult by both parties. Moreover, little is known about how people access other sources of care and information about prolonged fatigue, such as alternative medicine, self-help groups, lay others, and self care, in conjunction with or as an alternative to care from health professionals. This paper reviews the literature on the nature and extent of the problem prolonged fatigue represents for primary care, and on the use of formal and informal care for prolonged fatigue.

A 3-year audit of thyroid fine needle aspirates

Fine needle aspiration (FNA) cytology is an important adjunct to the preoperative management of thyroid swellings. It is a simple and highly cost effective procedure with a higher sensitivity for the detection of malignancy than ultrasound and radio-isotope scans. We audited a total of 208 aspirates performed over a 3-year period. In our experience 61% of solitary thyroid swellings can be diagnosed confidently on FNA cytology as either non-neoplastic (46%) or neoplastic (15%). Based on these two groups the sensitivity is 91% and specificity 94%. The specificity, however, decreases to 40% if the group reactive vs neoplastic, which comprises 10-15% of cases and requires surgical intervention, is included. The positive predictive value for malignant disease is 94% while the false-negative and -positive rates excluding the unsatisfactory and reactive vs neoplastic groups are low at 2.7% and 5.4%, respectively (involving non-neoplastic lesions and benign tumours only). There was no case of malignant cytology with a benign biopsy follow up.

Oocyte determination and the origin of polarity in Drosophila: the role of the spindle genes

The two main body axes in Drosophila become polarised as a result of a series of symmetry-breaking steps during oogenesis. Two of the sixteen germline cells in each egg chamber develop as pro-oocytes, and the first asymmetry arises when one of these cells is selected to become the oocyte. Anterior-posterior polarity originates when the oocyte then comes to lie posterior to the nurse cells and signals through the Gurken/Egfr pathway to induce the adjacent follicle cells to adopt a posterior fate. This directs the movement of the germinal vesicle and associated gurken mRNA from the posterior to an anterior corner of the oocyte, where Gurken protein signals for a second time to induce the dorsal follicle cells, thereby polarising the dorsal-ventral axis. Here we describe a group of five genes, the spindle loci, which are required for each of these polarising events. spindle mutants inhibit the induction of both the posterior and dorsal follicle cells by disrupting the localisation and translation of gurken mRNA. Moreover, the oocyte often fails to reach the posterior of mutant egg chambers and differentiates abnormally. Finally, double mutants cause both pro-oocytes to develop as oocytes, by delaying the choice between these two cells. Thus, these mutants reveal a novel link between oocyte selection, oocyte positioning and axis formation in Drosophila, leading us to propose that the spindle genes act in a process that is common to several of these events.

The mago nashi gene is required for the polarisation of the oocyte and the formation of perpendicular axes in Drosophila

BACKGROUND

Drosophila axis formation requires a series of inductive interactions between the oocyte and the somatic follicle cells. Early in oogenesis, Gurken protein, a member of the transforming growth factor alpha family, is produced by the oocyte to induce the adiacent follicle cells to adopt a posterior cell fate. These cells subsequently send an unidentified signal back to the oocyte to induce the formation of a polarised microtubule array that defines the anterior-posterior axis. The polarised microtubules also direct the movement of the nucleus and gurken mRNA from the posterior to the anterior of the oocyte, where Gurken signals a second time to induce the dorsal follicle cells, thereby polarising the dorsal-ventral axis.

RESULTS

In addition to its previously described role in the localisation of oskar mRNA, the mago nashi gene is required in the germ line for the transduction of the polarising signal from the posterior follicle cells. Using a new in vivo marker for microtubules, we show that mago nashi mutant oocytes develop a symmetric microtubule cytoskeleton that leads to the transient localisation of bicoid mRNA to both poles. Furthermore, the oocyte nucleus often fails to migrate to the anterior, causing the second Gurken signal to be sent in the same direction as the first. This results in a novel phenotype in which the anterior of the egg is ventralised and the posterior dorsalised, demonstrating that the migration of the oocyte nucleus determines the relative orientation of the two principal axes of Drosophila. The mago nashi gene is highly conserved from plants to animals, and encodes a protein that is predominantly localised to nuclei.

CONCLUSIONS

The mago nashi gene plays two essential roles in Drosophila axis formation: it is required downstream of the signal from the posterior follicle cells for the polarisation of the oocyte microtubule cytoskeleton, and has a second, independent role in the localisation of oskar mRNA to the posterior of the oocyte.

Identifying individuals with high fat levels and low P:S ratios, in their diets, for intensive dietary intervention

OBJECTIVES

To assess whether simple scores from a dietary questionnaire could identify those with high dietary fat or low P:S ratio intakes, for intensive dietary intervention.

DESIGN

Cross-sectional and longitudinal studies.

SETTING

Community setting in the Hunter Region of New South Wales, Australia.

SUBJECTS

Two random samples of adults 35-69 years from the electoral roll. In the cross-sectional study 287/322 (86%) subjects completed the diet questionnaire and a reference standard questionnaire. In the longitudinal study 546/653 (84%) of subjects completed the diet questionnaire, and had blood cholesterol measured on two occasions, 3 months apart.

MAIN OUTCOME MEASURES

In the cross-sectional study, the simple scores of total fat intake (Fat Intake Score) and P:S ratio (Unsaturated Score) were compared with the daily intakes of total fat and P:S ratio obtained from the standard questionnaire. In the longitudinal study, changes in the scores were compared with changes in blood total cholesterol.

RESULTS

A Fat Intake Score of greater than 125 had the best receiver operator characteristics for identifying high total fat intake (> 100 g/day: sensitivity = 67%, specificity = 70%). An Unsaturated Score of less than 0.3 had the best characteristics for identifying a low P:S ratio (< 0.5: sensitivity = 63%, specificity = 60%). Subjects who decreased Fat Intake Score by one category, had a fall in blood cholesterol of 0.14 mmol L-1 (95% confidence interval (CI) = 0.01-0.26 mmol L-1), while those decreasing by two categories decreased their blood cholesterol by 0.56 mmol L-1 (95% CI = 0.30-0.86 mmol L-1). Subjects increasing their Unsaturated Score category had a fall in blood cholesterol of 0.17 mmol L-1 (95% CI = 0.02-0.32 mmol L-1).

CONCLUSION

Simple dietary scores can identify those with high fat intakes, and monitor changes related to changes in blood cholesterol levels.

A 3 year audit of fine needle aspirates from a symptomatic breast clinic

A total of 2431 fine needle aspirates of symptomatic breast lumps was performed on 2096 patients over the last three years at the weekly head, neck and breast clinic at the Belfast City Hospital Trust. Diagnostic accuracy was achieved within the recommended standards although the "insufficient" rate was high at 31.8%. False negative and positive rates were low and the positive predictive value for malignancy was 99%. Excision biopsy for benign breast disease had decreased by almost a third during this period. Fine needle aspiration cytology is a highly accurate and cost-effective technique for the investigation of symptomatic breast lumps and results in significant savings.