810 Ischaemic Gallbladder Volvulus Within a Parastomal Hernia: Case Report and Literature Review

Case presentation

An 87-year-old female presented with 24 hours of severe central abdominal pain, preceded by five months of intermittent pain, and weight loss. Surgical history subtotal: colectomy and end ileostomy for ischaemia. Examination demonstrated generalised tenderness and longstanding parastomal hernia.

Abdominal CT demonstrated an oedematous gallbladder contained within the parastomal hernia and emergency laparotomy was performed. The gallbladder was twisted 360 degrees within the hernia and cholecystectomy and suture repair of parastomal hernia were performed.

Literature review: A 2013 review found most cases were diagnosed intra-operatively. Subsequent case reports were reviewed to identify contemporary practice.

Method

A pubmed search for “gallbladder volvulus”, 2012-2019 was performed. Articles meeting the inclusion criteria (gallbladder volvulus, english language, >18 years old, documented preoperative assessment and management) were analysed. Non-human and duplicate cases were excluded.

Results

24/43 screened cases met the criteria, including one within a parastomal hernia. 79% (19/24) were female, 50% (12/24) age >80. Although 96% (23/24) underwent imaging, only 38% (9/24) were diagnosed pre-operatively. One death was reported after non-operative management. 21 cases reported an operative approach with 48% (10/21) completed laparoscopically.

Conclusions

Gallbladder volvulus remains rare and difficult to identify on imaging.

P113 Starting a research collaborative in the midst of a pandemic – the Humberside experience

Introduction

The COVID-19 pandemic severely impacted research activities. Large international research collaboratives have successfully produced high quality COVID-related research. We aimed to investigate factors that influence trainee engagement in collaborative research and quantify engagement in our local area to propose methods to ensure all trainees have the opportunity to take part in impactful research.

Methods

This is a mixed methods study consisting of a survey to trainees regarding their experiences in research and an assessment of engagement in COVID-related research. The survey was circulated to undergraduates and trainees of all grades in February 2020.

Results

Engagement with the survey was poor, with a < 10% return rate. 43% of respondents stated that they had no experience of research. Engagement with collaborative research was popular, with responders declaring involvement with at least 7 other collaboratives. Reasons for participating in research were improving patient care (23%), producing high quality research (19%) and CV building (19%). Barriers included perceived lack of time (23%) and lack of knowledge about research (23%).

The CASSH collaborative co-ordinated the local response to COVIDSurg, COVIDSurg|Cancer and the COVER study, involving 20 trainees contributing data on 368 patients.

Conclusions

All research collaboratives rely on the enthusiasm of participants in order to succeed. We have presented some of the motivators and barriers to participation in our region and outlined how we have built on national projects to improve engagement on a local level. Further projects are planned to capitalise on this improved engagement.

P100 Recruitment barriers in multicentre collaborative studies as demonstrated by a single unit experience of the Management of Acutely Symptomatic Hernias (MASH) study

Introduction

MASH is a multi-centre prospective cohort study assessing the management of patients presenting with symptomatic abdominal wall hernia. Consenting patients are recruited during acute admission, with telephone follow up at day 30 and 90. We performed a retrospective review of all patients referred to a single general surgical unit with a symptomatic hernia to quantify recruitment rate and identify barriers to recruitment.

Methods

Patients meeting the inclusion criteria 1st August to 18th September were identified from prospective handover lists and electronic records and compared to the prospectively compiled screening log. Reason for not enrolment was coded according to protocol with an additional code added for patients not identified at time of admission.

Results

8/23 (35%) eligible patients were enrolled. 15/23 (65%) were not enrolled due to; Patient not identified at time of admission n = 9 (60%), declined n = 2 (13.3%), too unwell to consent n = 2 (13.3%), translational barrier n = 1 (6.6%) and lacking capacity n = 1 (6.6%). Patients not identified at time of admission included those seen by clinicians not involved in study (new starters and locums) and those discharged directly from A&E with insufficient time and resources to gain consent.

Conclusion

In our unit 65% of eligible patients were not recruited, the majority of whom were missed at time of presentation. This study will generate important information on management and outcomes of acute hernias however strategies are required to recognise and mitigate recruitment bias. Staff turnover may be a significant factor in prospective studies, particularly those prolonged during the COVID-19 pandemic.

Is There a Benefit of Combining Immunotherapy and Radiotherapy in Bladder Cancer?

Immune checkpoint inhibitors have transformed the management of patients with metastatic urothelial cancer, by leading to long-term response and prolongation of survival in a subset of patients. Unfortunately, only one in five patients with metastatic urothelial cancer responds to anti-programmed death ligand-1 ([AQ1]anti-PD-1) monotherapy. Preclinical and early clinical evidence indicates that radiotherapy not only acts locally, but also exerts systemic anti-tumour effects by modulating the immune system. It is hypothesised that combining checkpoint inhibitors with radiotherapy might enhance an anti-tumour immune response and increase response rates. So far, a handful of early phase clinical trials have been performed seeking to answer this question in urothelial cancer patients. The current review summarises the available preclinical and clinical evidence on radiotherapy/immunotherapy combinations in locally advanced and metastatic bladder cancer and suggests future avenues worthy of exploration.

KIF5A and the contribution of susceptibility genotypes as a predictive biomarker for multiple sclerosis

There is increasing interest in the development of multiple sclerosis (MS) biomarkers that reflect central nervous system tissue injury to determine prognosis. We aimed to assess the prognostic value of kinesin superfamily motor protein KIF5A in MS by measuring levels of KIF5A in cerebrospinal fluid (CSF) combined with analysis of single nucleotide polymorphisms (SNPs; rs12368653 and rs703842) located within a MS susceptibility gene locus at chromosome 12q13-14 region. Enzyme-linked immunosorbent assay was used to measure KIF5A in CSF obtained from two independent biobanks comprising non-inflammatory neurological disease controls (NINDC), clinically isolated syndrome (CIS) and MS cases. CSF KIF5A expression was significantly elevated in progressive MS cases compared with NINDCs, CIS and relapsing-remitting MS (RRMS). In addition, levels of KIF5A positively correlated with change in MS disease severity scores (EDSS, MSSS and ARMSSS), in RRMS patients who had documented disease progression at 2-year clinical follow-up. Copies of adenine risk alleles (AG/AA; rs12368653 and rs703842) corresponded with a higher proportion of individuals in relapse at the time of lumbar puncture (LP), higher use of disease-modifying therapies post LP and shorter MS duration. Our study suggests that CSF KIF5A has potential as a predictive biomarker in MS and further studies into the potential prognostic value of analysing MS susceptibility SNPs should be considered.

Glucocorticoid and inflammatory reactivity to a repeated physiological stressor in insomnia disorder

Despite known associations of insomnia disorder with alterations in cytokine and glucocorticoid (GC) production, neither the sensitivity of immune cells to a GC signal nor the reactivity of the hypothalamus-pituitary-adrenal (HPA) axis and inflammatory system to stress, or adaptation of these systems to repeated stress have been assessed in patients with insomnia. To investigate potential dysregulation in stress reactivity and adaptation to repeated exposure, a physiological stressor (the cold pressor test; CPT) was repeatedly administered to N = 20 participants with insomnia disorder (based on DSM-V, 18 females, age 30 ± 2.5 years) and N = 20 sex-matched healthy controls following an at-home actigraphy and in-laboratory PSG. HPA and inflammatory markers (serum cortisol, plasma interleukin [IL]-6) were measured at baseline/resting levels and following each of the three CPTs. In addition, sensitivity of monocytes to the synthetic GC dexamethasone was assessed in-vitro at baseline levels in order to examine the cortisol-IL-6 interplay at the cell level. Compared to healthy controls, individuals with insomnia disorder exhibited shorter sleep duration as assessed by actigraphy and PSG (p ≤ 0.05). HPA, but not inflammatory reactivity to the repeated CPT challenge was greater in insomnia disorder (p ≤ 0.05 for group effect), due to greater cortisol responses to the initial CPT (p ≤ 0.05). There were no between-group differences in the ability of the HPA to adapt to stress repetition nor in basal/resting levels of cortisol, IL-6, and GC sensitivity. These findings suggest that insomnia disorder potentiates HPA axis reactivity to initial/novel stressors, which may constitute a pathway underlying adverse health consequences in the long term.

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Insomnia disorder potentiates HPA, but not inflammatory reactivity to a novel stressor.

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The ability of the HPA axis to adapt to the repeated exposure to the same stressor is unchanged in insomnia.

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Basal/resting levels of cortisol, IL-6, and their interplay at cell level (i.e., GC sensitivity of monocytes) are unchanged in insomnia.

Female gender and diabetes mellitus increase the risk of recurrence after laparoscopic incisional hernia repair

BACKGROUND

Laparoscopic hernia repair is used widely for the repair of incisional hernias. Few case studies have focussed on purely 'incisional' hernias. This multicentre series represents a collaborative effort and employed statistical analyses to provide insight into the factors predisposing to recurrence of incisional hernia after laparoscopic repair. A specific hypothesis (ie, laterality of hernias as well as proximity to the xyphoid process and pubic symphysis predisposes to recurrence) was also tested.

METHODS

This was a retrospective study of all laparoscopic incisional hernias undertaken in six centres from 1 January 2004 to 31 December 2010. It comprised a comprehensive review of case notes and a follow-up using a structured telephone questionnaire. Patient demographics, previous medical/surgical history, surgical procedure, postoperative recovery, and perceived effect on quality of life were recorded. Repairs undertaken for primary ventral hernias were excluded. A logistic regression analysis was then fitted with recurrence as the primary outcome.

RESULTS

A total of 186 cases (91 females) were identified. Median follow-up was 42 months. Telephone interviews were answered by 115/186 (62%) of subjects. Logistic regression analyses suggested that only female sex (odds ratio (OR) 3.53; 95% confidence interval (CI) 1.39-8.97) and diabetes mellitus (3.54; 1-12.56) significantly increased the risk of recurrence. Position of the defect had no statistical effect.

CONCLUSIONS

These data suggest an increased risk of recurrence after laparoscopic incisional hernia repair in females and subjects with diabetes mellitus. These data will help inform surgeons and patients when considering laparoscopic management of incisional hernias. We recommend a centrally hosted, prospectively maintained national/international database to carry out additional research.

Reduced axonal motor protein expression in non-lesional grey matter in multiple sclerosis

Background:

Multiple sclerosis (MS) is a neurological disease characterised by central nervous system inflammation, demyelination, axonal degeneration and neuronal injury. Preventing neuronal and axon damage is of paramount importance in attempts to prevent disease progression. Intact axonal transport mechanisms are crucial to axonal integrity and evidence suggests these mechanisms are disrupted in MS. Anterograde axonal transport is mediated to a large extent through the kinesin superfamily proteins. Recently, certain kinesin superfamily proteins (KIF5A, KIF1B and KIF21B) were implicated in MS pathology.

Objectives:

To investigate the expression of KIF5A, KIF21B and KIF1B in MS and control post-mortem grey matter.

Methods:

Using both quantitative real-time polymerase chain reaction (PCR) and Immunodot-blots assays, we analysed the expression of kinesin superfamily proteins in 27 MS cases and 13 control cases not linked to neurological disease.

Results:

We have shown significant reductions in KIF5A, KIF21B and KIF1B messenger ribonucleic acid (mRNA) expression and also KIF5A protein expression in MS grey matter, as compared to control grey matter.

Conclusion:

We have shown significant reductions in mRNA and protein levels of axonal motor proteins in the grey matter of MS cases, which may have important implications for the pathogenesis of neuronal/axonal injury in the disease.

Fusion between human mesenchymal stem cells and rodent cerebellar Purkinje cells

AIMS

we explored whether cellular fusion and heterokaryon formation between human and rodent cells in the cerebellum of mice occurs after intravenous injection of human bone marrow-derived mesenchymal stem cells (MSCs). The influence of central nervous system inflammation on this process was also assessed. In addition, we examined whether tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma, factors associated with inflammation, increase cellular fusion between human MSCs and rodent cerebellar neurons in vitro.

METHODS AND RESULTS

human MSCs were intravenously injected into mice with experimental autoimmune encephalomyelitis (EAE) and control mice. After 22 days, mouse Purkinje cells expressing human Golgi Zone were found within the Purkinje cell layer of the cerebellum, indicating that fusion and heterokaryon formation had occurred. The numbers of heterokaryons in the cerebellum were markedly increased in mice with EAE compared with control mice. Rodent cerebellar neuronal cells labelled with enhanced green fluorescent proteinin vitro were co-cultured with human bone marrow-derived MSCs in the presence of TNF-alpha and/or IFN-gamma to determine their influence on fusion events. We found that fusion between MSCs and cerebellar neurons did occur in vitro and that the frequency of cellular fusion increased in the presence of TNF-alpha and/or IFN-gamma.

CONCLUSIONS

we believe that this is the first paper to define fusion and heterokaryon formation between human MSCs and rodent cerebellar neurons in vivo. We have also demonstrated that fusion between these cell populations occurs in vitro. These findings indicate that MSCs may be potential therapeutic agents for cerebellar diseases, and other neuroinflammatory and neurodegenerative disorders.

Evaluation of the processes of family-centred care for young children with intellectual disability in Western Australia

INTRODUCTION

Government early intervention services for children with intellectual disability (ID) in Western Australia have adopted the model of family-centred care. The aim of this study was to evaluate how well it was being practised, to describe the pattern of service utilization and to identify factors influencing parental perceptions of family-centred care.

METHODS

The study included children aged 0-6 years with ID, who were registered clients of Disability Services Commission, Western Australia. Parents completed a postal survey questionnaire about the frequency and type of services received and their perceptions of services using the Measure of Processes of Care (MPOC-56) questionnaire. Mean scores for the five MPOC domains were compared using anova against the independent variables of child age group, child diagnostic group, service type and frequency, place of residence, family and demographic variables. Significant variables in each domain were then entered into multivariate analyses.

RESULTS

Of 292 eligible families, 165 (59%) returned a completed questionnaire. While over 50% of children had contact with occupational, speech and physical therapists at least once per month, less than 20% of children had at least annual contact with either psychology or dental services. Families rated their satisfaction highest for 'respectful and supportive care' and lowest for 'providing general information'. Individual item analyses indicated less satisfaction with 'co-ordinated and comprehensive care'. Higher means were associated with more frequent contact with occupational therapy.

CONCLUSION

Overall respondents reported early intervention services for young children with ID in Western Australia provided satisfactory family-centred care by means of the 56-item MPOC. The frequency of contact with allied health professionals was positively associated with parental ratings of family-centred care. The study indicates under-servicing in dental care and psychology services.

Patterns of treatment of osteoradionecrosis with hyperbaric oxygen therapy in the United Kingdom

We aimed to find out the number of patients with osteoradionecrosis (ORN) being treated by hyperbaric chambers in the UK during 2006-07, and the protocols that were being used. We did a telephone survey of 76 chambers to find out whether they treated patients with ORN, how many patients they treated in 2006-07, what chamber pressure they used, the duration of each session, and the total number of sessions/patient. A total of 25 chambers treated 273 patients with ORN in 2006-07; 10 were listed by the British Hyperbaric Association (BHA) and 15 were at multiple sclerosis (MS) centres. MS centres treated 23 (8%) of patients with ORN with a variable number of sessions of shorter duration and lower pressures than the chambers listed by the BHA. Most BHA chambers treated patients at 2.2 ATA for 90 min/session with 30 preoperative and 10 postoperative sessions/patient.

Protecting axons in multiple sclerosis

Typically patients with multiple sclerosis (MS) experience acute episodes of neurological dysfunction, which recover followed, at a later stage, by slow and insidious accumulation of disability (disease progression). Disease progression reflects axon damage and loss within the central nervous system. However, the precise mechanism of axon injury in MS is not clear. Inflammation occurring during acute relapses undoubtedly causes some degree of acute axon damage, but epidemiological data and treatment studies have suggested that inflammation alone is not the sole cause of axonopathy. Indeed, there appears to be dissociation between inflammation and disease progression once a certain level of clinical disability has been reached because immune suppression in patients who have established disease progression does not halt the slow decrease of function. The slow and insidious loss of neurological function that occurs during the progressive phase of the disease implies a degenerative process. Whether axon drop-out occurs at these later stages because of previous inflammatory damage to axons; because of low grade inflammation causing damage to already vulnerable demyelinated axons; because of loss of trophic environment for axons to survive; or as part of a completely independent neurodegenerative process is not clear. Understanding disease mechanisms involved in the axonopathy of MS allows for the development of rational therapies for disease progression.

Constraints to Microbial Food Safety Policy: Opinions from Stakeholder Groups along the Farm to Fork Continuum

This exploratory qualitative study was conducted to identify constraints to microbial food safety policy in Canada and the USA from the perspective of stakeholder groups along the farm to fork continuum. Thirty-seven stakeholders participated in interviews or a focus group where semi-structured questions were used to facilitate discussion about constraints to policy development and implementation. An emergent grounded theory approach was used to determine themes and concepts that arose from the data (versus fitting the data to a hypothesis or a priori classification). Despite the plurality of stakeholders and the range of content expertise, participant perceptions emerged into five common themes, although, there were often disagreements as to the positive or negative attributes of specific concepts. The five themes included challenges related to measurement and objectives of microbial food safety policy goals, challenges arising from lack of knowledge, or problems with communication of knowledge coupled with current practices, beliefs and traditions; the complexity of the food system and the plurality of stakeholders; the economics of producing safe food and the limited resources to address the problem; and, issues related to decision-making and policy, including ownership of the problem and inappropriate inputs to the decision-making process. Responsibilities for food safety and for food policy failure were attributed to all stakeholders along the farm to fork continuum. While challenges regarding the biology of food safety were identified as constraints, a broader range of policy inputs encompassing social, economic and political considerations were also highlighted as critical to the development and implementation of effective food safety policy. Strategies to address these other inputs may require new, transdisciplinary approaches as an adjunct to the traditional science-based risk assessment model.

The Effect of Colored Lenses on the Visual Evoked Response in Children With Visual Stress

PURPOSE

Some children with visual stress and/or headaches have fewer symptoms when wearing colored lenses. Although subjective reports of improved perception exist, few objective correlates of these effects have been established.

METHODS

In a pilot study, 10 children who wore Intuitive Colorimeter lenses, and claimed benefit, and two asymptomatic children were tested. Steady-state potentials were measured in response to low contrast patterns modulating at a frequency of 12 Hz. Four viewing conditions were compared: 1) no lens; 2) Colorimeter lens; 3) lens of complementary color; and 4) spectrally neutral lens with similar photopic transmission.

RESULTS

The asymptomatic children showed little or no difference between the lens and no lens conditions. When all the symptomatic children were tested together, a similar result was found. However, when the symptomatic children were divided into two groups depending on their symptoms, an interaction emerged. Children with visual stress but no headaches showed the largest amplitude visual evoked potential response in the no lens condition, whereas those children whose symptoms included severe headaches or migraine showed the largest amplitude visual evoked potential response when wearing their prescribed lens.

CONCLUSIONS

The results suggest that it is possible to measure objective correlates of the beneficial subjective perceptual effects of colored lenses, at least in some children who have a history of migraine or severe headaches.

150 ENVIRONMENT OF THE EARLY EMBRYO AND ITS EFFECT ON DEVELOPMENT AND POSTNATAL LIFE

We have investigated the impact of mouse early embryo in vitro culture environment on (a) short-term blastocyst development and (b) long-term postnatal growth and physiology after embryo transfer. In vitro-developed blastocysts, cultured from the 2-cell stage, had reduced inner cell mass (ICM) and trophectoderm (TE) cell numbers when compared to in vivo-derived blastocysts at 96 h post-hCG (n = 13–39, P < 0.05). Despite the retardation in blastocyst development, the ICM:TE ratio was equivalent in both treatment groups. Using embryo transfer techniques, we compared the postnatal development of embryos cultured in vitro from the 2-cell to the blastocyst stage (termed “in vitro” mice) with offspring generated from blastocysts developed in vivo, but which also underwent embryo transfer (termed “in vivo” mice). These two treatment groups were in turn compared with mice derived from naturally mated mothers, which had their mean litter size at birth adjusted to a size comparable with that of the in vitro and in vivo mice (a mean of 6 animals) and which had not been transferred. All data were analyzed using a multilevel random effects regression model which took into account between-mother and within-mother variation in litter size for parameters measured from individual animals. No significant differences in birth weight were observed between in vitro and in vivo offspring. However, in vitro offspring were significantly lighter than in vivo offspring in a gender-dependent manner at 2 weeks of age (males, P = 0.009) and at 6 and 11 weeks of age (females, P = 0.037 and 0.035, respectively). In addition, at 4 weeks of age, the in vivo males became significantly lighter when compared to the naturally mated males (P = 0.034). At 8 weeks of age, the in vivo females had a significantly elevated systolic blood pressure when compared to the in vitro females (P = 0.003); however, at 21 weeks of age, both in vitro males and females had a significantly elevated blood pressure when compared to in vivo offspring (P < 0.003). At 8, 15, and 21 weeks of age, offspring derived from transferred embryos developed with significantly elevated systolic blood pressure when compared to non-embryo transfer offspring (P < 0.05). No significant differences in serum angiotensin-converting enzyme activity (a potent regulator of systolic blood pressure) was observed between the treatment groups. Significantly altered liver:body weight ratios were observed between the in vitro and in vivo males, and between the in vitro and the naturally mated (6) females (P < 0.038). All of the above data are independent of litter size. These data support the hypothesis that early embryo environment can influence postnatal growth and cardiovascular physiology. This research was funded by an MRC research grant to TPF, and by a DOHaD studentship.

Clinical characteristics and methods of treatment of patients with stable coronary heart disease in the primary care settings--the results of the Polish, Multicentre Angina Treatment Pattern (ATP) study

For further improvement of coronary heart disease (CHD) management large epidemiological studies are required to characterise the real population of patients with CHD, treated in the primary care settings, and to evaluate how the guidelines are implemented in the everyday clinical practice. The aim of the Angina Treatment Pattern (ATP) survey was to characterise (i) the population of patients, treated by the primary care physicians for stable CHD, (ii) the methods applied by the primary care physicians to establish diagnosis of CHD and (iii) the pharmacological therapies for CHD. Across Poland, 397 primary care physicians were randomly selected. They recruited 7420 patients (49% men; mean age, 62 +/- 10 years; range: 25-93 years), treated for stable CHD. The duration of CHD was 7.4 +/- 6.6 years (range: 6 months-50 years), 2750 (37%) patients had myocardial infarction. The following risk factors of CHD were present: arterial hypertension in 58%, dyslipidaemia in 52%, smoking in 40%, family history of CHD in 56% and obesity or overweight in 73% of patients. Primary care physicians based a diagnosis of CHD predominantly on a history of anginal pain (in 33% patients), accompanied either by abnormal resting ECG or positive exercise test (in additional 31% patients). Only in 5% of patients, coronary angiography was applied to diagnose CAD. The following groups of drugs have been used: long-acting nitrates in 90%, anti-platelet drugs or anti-coagulants in 71% (aspirin in 65%), angiotensin-converting enzyme inhibitors in 51%, beta-blockers in 48%, calcium antagonists 31%, hypolipaemic drugs in 23% (statins in 10%) and metabolic agents in 16% of patients. Despite an extensive use of classical anti-anginal drugs (including at least one of the following: long-acting nitrates, beta-blockers, calcium antagonists in 95% of patients), 85% of patients still complained of anginal symptoms. Neither prevalence of angina among patients nor nitroglycerin intake depended on the number of anti-anginal drugs taken (monotherapy vs. combination therapy: 82% vs. 86% and 4.9 vs. 5.3 doses weekly, respectively). Among the primary care physicians, the methods used to establish a CHD diagnosis and the mode of CHD management are far from optimal. The results of the ATP study confirm the need for further intensification of activities to improve the process of diagnosis and management among patients with CHD, treated by the family doctors.

A role for oligodendrocyte-derived IGF-1 in trophic support of cortical neurons

Neurons and glia interact in the development of mammalian central nervous systems and in the maintenance of stable myelinated axons. Recent evidence suggests a role for oligodendrocytes in providing trophic support for neurons during development and in the mature nervous system. This work prompted us to study oligodendrocyte influences on neuronal survival and death in vitro. Rat embryonic cortical neurons were co-cultured with purified oligodendrocytes at different developmental stages and separately with oligodendrocyte-conditioned medium. Neuronal survival was measured by immunocytochemistry and 3H-GABA uptake. Neurons show a marked increase in survival when co-cultured directly with oligodendrocyte precursors (OPCs) and differentiated oligodendrocytes. Neurons cultured in the presence of OPCs separated by a permeable membrane and those cultured in medium conditioned by oligodendrocytes also show a significant increase in survival. Medium conditioned by differentiated oligodendrocytes provides a greater survival effect than medium conditioned by OPCs. Neutralising antibodies to IGF-1, but not to other candidate trophic factors, block the soluble survival effect of oligodendrocytes. Cells of the oligodendrocyte lineage produce IGF-1 and recombinant IGF-1 promotes neuronal survival under identical conditions. This study provides evidence that OPCs and differentiated oligodendrocytes support neuronal survival by both contact-mediated and soluble mechanisms and that IGF-1 significantly contributes to this effect.

Determining the need for hip and knee arthroplasty: the role of clinical severity and patients' preferences

BACKGROUND

Area variation in the use of surgical interventions such as arthroplasty is viewed as concerning and inappropriate.

OBJECTIVES

To determine whether area arthroplasty rates reflect patient-related demand factors, we estimated the need for and the willingness to undergo arthroplasty in a high- and a low-use area of Ontario, Canada.

RESEARCH DESIGN

Population-based mail and telephone survey.

SUBJECTS

All adults aged > or =55 years in a high (n = 21,925) and low (n = 26,293) arthroplasty use area.

MEASURES

We determined arthritis severity and comorbidity with questionnaires, established the presence of arthritis with examination and radiographs, and evaluated willingness to have arthroplasty with interviews. Potential arthroplasty need was defined as severe arthritis, no absolute contraindication for surgery, and evidence of arthritis on examination and radiographs. Estimates of need were then adjusted for patients' willingness to undergo arthroplasty.

RESULTS

Response rates were 72.0% for questionnaires and interviews. The potential need for arthroplasty was 36.3/1,000 respondents in the high-rate area compared with 28.5/1,000 in the low-rate area (P <0.0001). Among individuals with potential need, only 14.9% in the high-rate area and 8.5% in the low-rate area were definitely willing to undergo arthroplasty (P = 0.03), yielding adjusted estimates of need of 5.4/1,000 and 2.4/1,000 in the high- and low-rate areas, respectively.

CONCLUSIONS

Demonstrable need and willingness were greater in the high-rate area, suggesting these factors explain in part the observed geographic rate variations for this procedure. Among those with severe arthritis, no more than 15% were definitely willing to undergo arthroplasty, emphasizing the importance of considering both patients' preferences and surgical indications when evaluating need and appropriateness of rates for surgery.

Small GTPases in Dictyostelium: lessons from a social amoeba

Although the process of sequencing the Dictyostelium genome is not complete, it is already producing surprises, including an unexpectedly large number of Ras- and Rho-subfamily GTPases. Members of these families control a wide variety of cellular processes in eukaryotes, including proliferation, differentiation, cell motility and cell polarity. Comparison of small GTPases from Dictyostelium with those from higher eukaryotes provides an intriguing view of their cellular and evolutionary roles. In particular, although mammalian Ras proteins interact with several signalling pathways, the Dictyostelium pathways appear more linear, with each Ras apparently performing a specific cellular function.

A novel Dictyostelium RasGEF is required for normal endocytosis, cell motility and multicellular development

BACKGROUND

Dictyostelium possesses a surprisingly large number of Ras proteins and little is known about their activators, the guanine nucleotide exchange factors (GEFs). It is also unclear, in Dictyostelium or in higher eukaryotes, whether Ras pathways are linear, with each Ras controlled by its own GEF, or networked, with multiple GEFs acting on multiple Ras proteins.

RESULTS

We have identified the Dictyostelium gene that encodes RasGEFB, a protein with homology to known RasGEFs such as the Son-of-sevenless (Sos) protein. Dictyostelium cells in which the gene for RasGEFB was disrupted moved unusually rapidly, but lost the ability to perform macropinocytosis and therefore to grow in liquid medium. Crowns, the sites of macropinocytosis, were replaced by polarised lamellipodia. Mutant cells were also profoundly defective in early development, although they eventually formed tiny but normally proportioned fruiting bodies. This defect correlated with loss of discoidin Igamma mRNA, a starvation-induced gene, although other genes required for development were expressed normally or even precociously. RasGEFB was able to rescue a Saccharomyces CDC25 mutant, indicating that it is a genuine GEF for Ras proteins.

CONCLUSIONS

RasGEFB appears to be the principal activator of the RasS protein, which regulates macropinocytosis and cell speed, but it also appears to regulate one or more other Ras proteins.

Dictyostelium RasD is required for normal phototaxis, but not differentiation

RasD, a Dictyostelium homolog of mammalian Ras, is maximally expressed during the multicellular stage of development. Normal Dictyostelium aggregates are phototactic and thermotactic, moving towards sources of light and heat with great sensitivity. We show that disruption of the gene for rasD causes a near-total loss of phototaxis and thermotaxis in mutant aggregates, without obvious effects on undirected movement. Previous experiments had suggested important roles for RasD in development and cell-type determination. Surprisingly, rasD(-) cells show no obvious changes in these processes. These cells represent a novel class of phototaxis mutant, and indicate a role for a Ras pathway in the connections between stimuli and coordinated cell movement.

Purification and cloning of phosphatidylinositol transfer proteins from Dictyostelium discoideum: homologues of both mammalian PITPs and Saccharomyces cerevisiae sec14p are found in the same cell

Soluble phosphatidylinositol transfer proteins (PITPs) have important roles in lipid-mediated signalling as well as in membrane traffic. Two PITPs (alpha and beta) have been cloned from mammalian cells, which are unrelated in sequence to yeast PITP (the product of the SEC14 gene). However, all three PITPs can perform interchangeably to reconstitute function in mammalian cells. We have now purified the major PITP from the cytoplasm of Dictyostelium discoideum and cloned the gene. This protein, DdPITP1, is homologous with mammalian PITPalpha and PITPbeta. We have also cloned a second gene (DdPITP2) related in sequence to DdPITP1. In addition, an independently cloned cDNA encodes a relative of the SEC14 family of yeast PITPs. DdPITP1, DdPITP2 and DdSec14 proteins were all able to mediate the transfer of PtdIns from one membrane compartment to another; they thus exhibited the hallmark of PITPs. Secondly, all three PITPs were able to rescue phospholipase C-mediated phosphoinositide hydrolysis in PITP-depleted HL60 cells, indicating that all three PITPs were capable of stimulating phosphoinositide synthesis. The identification of PITPs related to both mammalian PITPs and yeast Sec14p in a single organism will provide a unique opportunity to examine the functions of this class of protein with genetic approaches.

Tropisetron reduces postoperative vomiting in children undergoing tonsillectomy

In this patient, parent and investigator blinded, randomized, placebo-controlled study, children undergoing tonsillectomy (mean age 6.4 years) received either intravenous placebo (n=36) or tropisetron 0.2 mg.kg-1 up to 5 mg (n=35) at induction of anaesthesia with halothane, nitrous oxide and oxygen. Morphine and paracetamol were given in theatre for postoperative pain. Episodes of vomiting were recorded during the first 24 h after surgery. Intravenous tropisetron was significantly (P<0.001, chi-squared) more effective than placebo in controlling the incidence and frequency of emesis during the first 24 h: vomiting was reduced from 89% to 46% and the mean number of vomits from 4.6 to 2.4. Minor side-effects occurred equally in both the placebo and active groups. Intravenous tropisetron is an effective and safe antiemetic for reducing postoperative vomiting in children undergoing tonsillectomy or adenotonsillectomy.

Maternal HIV-1 and HIV-2 infection and child survival in The Gambia

OBJECTIVE

To compare the survival of children born to HIV-1 or HIV-2 seropositive mothers with that of children born to HIV-seronegative mothers and to evaluate risk factors for mortality.

DESIGN

Physician-blinded prospective study.

METHODS

One hundred and one HIV-1-seropositive, 243 HIV-2-seropositive pregnant women, and 468 HIV-seronegative women (control group) matched by age, parity, and health centre, were followed up in a study of mother-to-child transmission of HIV. Mothers and children were seen at 2 and 6 months of age and subsequently followed at 3-monthly intervals up to 18 months of age. HIV infection in children was diagnosed by polymerase chain reaction at 2, 9 or 18 months and by antibody assays at 18 months.

RESULTS

Fifteen per cent of children born to HIV-1-infected mothers died compared with 7% of children born to HIV-2-infected mothers [hazard ratio, 2.3; 95% confidence interval (CI), 1.1-4.7; P = 0.02], and 6% of HIV-seronegative mothers (hazard ratio, 2.6; 95% CI, 1.4-5.0; P = 0.003). Six of the 17 children known to be HIV-1 infected died compared with none among the eight HIV-2-infected children (P = 0.13). High proviral load in the babies, high antenatal maternal RNA plasma viral load, and maternal death increased child mortality significantly.

CONCLUSIONS

More children born to HIV-1-infected mothers died in comparison with those born to HIV-2-infected mothers or to mothers from the control group. This effect was due to excess death in HIV-1-infected infants which was associated with a high viral load in the affected mother and child.

Coloured overlays, text, and texture

In four studies children were asked to read aloud a passage of randomly ordered common words with and without a coloured sheet of plastic (overlay) placed upon the page. The children's rate of reading increased with the overlay, for some children more than for others. The children were also asked to undertake a test of texture segmentation in which targets consisting of a structured texture had to be distinguished from within a random background texture. The texture segmentation was improved when the overlay was used, again for some children more than for others. The improvement in texture segmentation was, in general, correlated with the improvement in rate of reading. Slower readers were generally poorer at texture segmentation. The implications for reading, for texture segmentation, and for clinical tests of vision are discussed.

The Dictyostelium RasS protein is required for macropinocytosis, phagocytosis and the control of cell movement

Endocytosis and cell migration both require transient localised remodelling of the cell cortex. Several lines of evidence suggest a key regulatory role in these activities for members of the Ras family of small GTPases. We have generated Dictyostelium cells lacking one member of this family, RasS, and the mutant cells are perturbed in endocytosis and cell migration. Mutant amoebae are defective in phagocytosis and fluid-phase endocytosis and are impaired in growth. Conversely, the rasS(-)cells show an enhanced rate of cell migration, moving three times faster than wild-type controls. The mutant cells display an aberrant morphology, are highly polarised, carry many elongated actin protrusions and show a concomitant decrease in formation of pinocytic crowns on the cell surface. These morphological aberrations are paralleled by changes in the actin cytoskeleton, with a significant proportion of the cortical F-actin relocalised to prominent pseudopodia. Rapid migration and endocytosis appear to be mutually incompatible and it is likely that RasS protein is required to maintain the normal balance between these two actin-dependent processes.

Serotonergic dysfunction in women with pure premenstrual dysphoric disorder: is the fenfluramine challenge test still relevant?

The fenfluramine (FEN) neuroendocrine challenge paradigm, which involves measuring the response of prolactin (PRL) release to an oral challenge dose of FEN, provides a means of assessing serotonin (5-HT) function. The purpose of this study was to ascertain the role of 5-HT in premenstrual dysphoric disorder (PMDD) by measuring: (1) PRL and cortisol (CORT) responses to FEN; and (2) platelet 3H-imipramine binding levels, in females with pure PMDD (without a past or present comorbid mood disorder) in comparison to healthy controls. FEN challenge tests were administered to nine female patients with pure PMDD and nine healthy female controls during the follicular and late luteal phases of a menstrual cycle. There were no differences in the PRL response to FEN for women with PMDD compared to healthy controls. However, the trend toward a delayed response to FEN and a significant negative correlation between delta(max) PRL and basal CORT in patients but not in controls during both phases of the menstrual cycle suggest an underlying 5-HT dysfunction in patients as compared to controls. This is further supported by the finding of significantly lower Bmax 3H-imipramine binding levels in the patients during the late luteal phase.

Photic stimulation: standardization of screening methods

PURPOSE

Differences in methodology of intermittent photic stimulation within and between countries in Europe make collaborative research and interpretation of results difficult.

METHOD

Experts in the field of photic stimulation from European countries have given an overview of methods used in routine photic stimulation. A consensus meeting was organized in May 1996 in the Netherlands.

RESULTS

Methodology, including specification of a photo stimulator, procedure of photic stimulation, and interpretation of EEG results, has been defined according to available scientific and clinical knowledge.

CONCLUSIONS

Consensus was reached in setting up a safe, quick, simple and reliable method to determine whether or not patients are photosensitive. A specification of an international standard for intermittent photic stimulation in the routine EEG examination is given with the purpose of improving patient care and facilitating collaborative research.