Mitochondrial phenotypes in iPSC AD models

BACKGROUND

Mitochondrial dysfunction is observed in Alzheimer's disease (AD). Altered mitochondrial respiration, cytochrome oxidase (COX) Vmax, and mitophagy are observed in human subjects and animal models of AD. Models derived from induced pluripotent stem cells (iPSCs) may not recapitulate these phenotypes after reprogramming from differentiated adult cells. We examined mitochondrial function across iPSC derived models including cerebral organoids, forebrain neurons, and astrocytes. Postmortem brain tissue was used as a comparison.

METHOD

iPSCs were reprogrammed from fibroblasts either from the University of Kansas Alzheimer's Disease Research Center (KU ADRC) cohort or purchased from WiCell. Postmortem brain samples were from the KU ADRC cohort when available. A total of four non-demented and four sporadic AD iPSC lines were examined. Postmortem brain tissue was derived from 9 ND and 12 AD subjects. iPSCs were differentiated into neurons, astrocytes, or cerebral organoids using StemCell Technologies protocols and reagents. iPSC derived models and postmortem brain tissue were subjected to mitochondrial respiration analysis using Seahorse XF technology and spectrophotometric COX Vmax assays. iPSC derived neurons and astrocytes underwent fluorescent assays to determine mitochondrial mass, mitochondrial membrane potential, and mitophagy levels.

RESULT

iPSC derived neurons and cerebral organoids showed reduced COX Vmax in AD subjects. These results were not observed in astrocytes. Postmortem human brain samples showed reduced COX Vmax in AD subjects. iPSC derived neurons had reduced mitochondrial respiration parameters, mitochondrial mass, mitophagy, mitochondrial membrane potential, and mitochondrial superoxide production. iPSC derived astrocytes had reduced mitochondrial respiration parameters but increased mitochondrial membrane potential and no change in mitochondrial superoxide production.

CONCLUSION

iPSC derived models from AD subjects show mitochondrial dysfunction phenotypes like what is observed in postmortem brain. As iPSCs do not maintain their epigenetic signatures after reprogramming the observed phenotypes are likely due to other somatic factors.

Prediction of intramuscular fat in lamb by visible and near-infrared spectroscopy in an abattoir environment

The study used visible and near-infrared spectroscopy (Vis-NIR) in a large commercial processing plant, to test a system for meat quality (intramuscular fat; IMF) data collection within a supply chain for UK lamb meat. Crossbred Texel x Scotch Mule lambs (n = 220), finished on grass on 4 farms and slaughtered across 2 months, were processed through the abattoir and cutting plant and recorded using electronic identification. Vis-NIR scanning of the cut surface of the M. longissimus lumborum produced spectral data that predicted laboratory-measured IMF% with moderate accuracy (R² 0.38-0.48). Validation of the Vis-NIR prediction equations on an independent sample of 30 lambs slaughtered later in the season, provided similar accuracy of IMF prediction (R² 0.54). Values of IMF from four different laboratory tests were highly correlated with each other (r 0.82-0.95) and with Vis-NIR predicted IMF (r 0.66-0.75). Results suggest scope to collect lamb loin IMF data from a commercial UK abattoir, to sort cuts for different customers or to feed back to breeding programmes to improve meat quality.

P6134Understanding non-attendance to an inner city tertiary centre heart failure clinic: a pilot project

Background

Tackling health inequalities is a priority in heart failure (HF). We do not fully understand why some patients do not attend their hospital HF clinic appointments. Currently when a patient DNAs (does not attend) they are offered a repeat appointment often months later or are discharged from the service with a request to the primary care physician to re-refer. Non-attendance represents a missed opportunity to improve patients' health.

Purpose

The purpose of this pilot was to look at the demographics and patient factors that contribute to non-attendance. The aim is to understand and personalise our DNA policy to reduce health inequality, improve outcomes, and reduce inefficiencies in our service.

Methods

The last consecutive 45 patients who DNAd HF clinic were identified and for each, a patient who did attend the same clinic date (Attender), was chosen at random (random.org). The demographics were obtained (age, ethnicity, contact details) and medical notes reviewed (LVEF%, co-morbidities). The patient address was scored for its Index of Multiple Deprivation (IMD) – a UK government dataset measuring relative deprivation by ranking 32,844 neighbourhoods nationally using 37 indicators across 7 domains of deprivation where neighbourhood 1 is the most deprived nationally. Patients were phoned up to three times to establish the patient's mode, duration and cost of their last journey to clinic and, for those patients who DNAd, to ascertain the reason for non-attendance.

Results

Demographic and medical history was obtained for all patients. It was not possible to contact 2/45 of the Attenders, and 13/45 of the DNA patients. There was no significant difference in age, gender, number of comorbidities, LVEF%, travel time, or travel cost between DNAs and attenders. The mean one-way journey time was 53.4 mins (range 15–210 mins) and the mean return journey cost was GBP ≤10.95 (range ≤0–≤80). Common reasons for non-attendance were not receiving appointment details, forgetting appointments, being unwell on the day and difficulties with travel. The IMD score for the patients who DNAd was significantly lower confirming these patients lived in more deprived areas (9436±5863 vs. 15414±7801, p<0.001) with 71% of DNA patient's addresses in the bottom third most deprived neighbourhoods nationally.

Figure 1

Conclusions

There was a significant difference in deprivation score between patients who attended and DNAd their clinics. In addition, we found that all patients were travelling up to an hour each way to attend clinic, and that the cost of travel may be a barrier to attendance, even in a healthcare system that is free at the point of delivery. Despite calling three times, we were unable to speak to 29% of patients who DNAd and 4% of the patients who attended their appointments. Work is ongoing to reduce our DNA rates and personalise our response in this deprived population, with the aim of improving engagement and health inequality.

Addressing the pitfalls when designing intervention studies to discover and validate biomarkers of habitual dietary intake

INTRODUCTION

Dietary exposure monitoring within populations is reliant on self-reported measures such as Food Frequency Questionnaires and diet diaries. These methods often contain inaccurate information due to participant misreporting, non-compliance and bias. Urinary metabolites derived from individual foods could provide additional objective indicators of dietary exposure. For biomarker approaches to have utility it is essential that they cover a wide-range of commonly consumed foods and the methodology works in a real-world environment.

OBJECTIVES

To test that the methodology works in a real-world environment and to consider the impact of the major sources of likely variance; particularly complex meals, different food formulations, processing and cooking methods, as well as the dynamics of biomarker duration in the body.

METHODS

We designed and tested a dietary exposure biomarker discovery and validation strategy based on a food intervention study involving free-living individuals preparing meals and collecting urine samples at home. Two experimental periods were built around three consecutive day menu plans where all foods and drinks were provided (n = 15 and n = 36).

RESULTS

The experimental design was validated by confirming known consumption biomarkers in urinary samples after the first menu plan. We tested biomarker performance with different food formulations and processing methods involving meat, wholegrain, fruits and vegetables.

CONCLUSION

It was demonstrated that spot urine samples, together with robust dietary biomarkers, despite major sources of variance, could be used successfully for dietary exposure monitoring in large epidemiological studies.

INCIDENCE OF TEENAGE PREGNANCY IN GEORGIA AND AUSTRALIA. PATTERNS OF SOCIAL ACCEPTANCE AND RELATED HEALTHCARE CONCERNS

Teenage pregnancy has been a target for prevention in many countries. Teen motherhood may adversely influence social determinants of health, including education attainment, employment and reliance on welfare support. We compared socioeconomic factors and geographical influencers affecting teenage pregnancy and birth outcomes across Georgia and Australia. Georgia has a teenage pregnancy rate three times higher than Australia. However, there are similar proportions of contraceptive use between Georgian and Australian teenagers as well as increasing rates of sexual health literacy in both countries. Both countries, however, show a comparative deficiency in sexual health literacy for rural populations resulting in earlier sexual experiences in Georgia and higher teenage pregnancy rates in Australia with Indigenous teenage mothers over-represented. More age-appropriate sexual health and contraception education is required in both Georgia and Australia, especially for rural areas, Indigenous populations and ethnic minorities. Further research is needed to supply teenage pregnancy and birth data from Georgian population.

The Oncogenic Transcription Factor RUNX1/ETO Corrupts Cell Cycle Regulation to Drive Leukemic Transformation

Oncogenic transcription factors such as the leukemic fusion protein RUNX1/ETO, which drives t(8;21) acute myeloid leukemia (AML), constitute cancer-specific but highly challenging therapeutic targets. We used epigenomic profiling data for an RNAi screen to interrogate the transcriptional network maintaining t(8;21) AML. This strategy identified Cyclin D2 (CCND2) as a crucial transmitter of RUNX1/ETO-driven leukemic propagation. RUNX1/ETO cooperates with AP-1 to drive CCND2 expression. Knockdown or pharmacological inhibition of CCND2 by an approved drug significantly impairs leukemic expansion of patient-derived AML cells and engraftment in immunodeficient murine hosts. Our data demonstrate that RUNX1/ETO maintains leukemia by promoting cell cycle progression and identifies G1 CCND-CDK complexes as promising therapeutic targets for treatment of RUNX1/ETO-driven AML.

Short Term Development and Fate of MGE-Like Neural Progenitor Cells in Jaundiced and Non-Jaundiced Rat Brain

Neonatal hyperbilirubinemia targets specific brain regions and can lead to kernicterus. One of the most debilitating symptoms of kernicterus is dystonia, which results from bilirubin toxicity to the globus pallidus (GP). Stem cell transplantation into the GP to replace lost neurons and restore basal ganglia circuits function is a potential therapeutic strategy to treat dystonia in kernicterus. In this study we transplanted human medial ganglionic eminence (MGE)-like neural progenitor cells (NPCs) that we differentiated into a primarily gamma-aminobutyric acid (GABA)ergic phenotype, into the GP of non-immunosuppressed jaundiced (jj) and non-jaundiced (Nj) rats. We assessed the survival and development of graft cells at three time-points post-transplantation. While grafted MGE-like NPCs survived and generated abundant fibers in both jj and Nj brains, NPC survival was greater in the jj brain. These results were consistent with our previous finding that excitatory spinal interneuron-like NPCs exhibited a higher survival rate in the jj brain than in the Nj brain. Our findings further support our hypothesis that slightly elevated bilirubin levels in the jj brain served as an antioxidant and immunosuppressant to protect the transplanted cells. We also identified graft fibers growing toward brain regions that receive projections from the GP, as well as host fibers extending toward the graft. These promising findings suggest that MGE-like NPCs may have the capacity to restore the circuits connecting GP and other nuclei.

Merits of random forests emerge in evaluation of chemometric classifiers by external validation

Real-world applications will inevitably entail divergence between samples on which chemometric classifiers are trained and the unknowns requiring classification. This has long been recognized, but there is a shortage of empirical studies on which classifiers perform best in 'external validation' (EV), where the unknown samples are subject to sources of variation relative to the population used to train the classifier. Survey of 286 classification studies in analytical chemistry found only 6.6% that stated elements of variance between training and test samples. Instead, most tested classifiers using hold-outs or resampling (usually cross-validation) from the same population used in training. The present study evaluated a wide range of classifiers on NMR and mass spectra of plant and food materials, from four projects with different data properties (e.g., different numbers and prevalence of classes) and classification objectives. Use of cross-validation was found to be optimistic relative to EV on samples of different provenance to the training set (e.g., different genotypes, different growth conditions, different seasons of crop harvest). For classifier evaluations across the diverse tasks, we used ranks-based non-parametric comparisons, and permutation-based significance tests. Although latent variable methods (e.g., PLSDA) were used in 64% of the surveyed papers, they were among the less successful classifiers in EV, and orthogonal signal correction was counterproductive. Instead, the best EV performances were obtained with machine learning schemes that coped with the high dimensionality (914-1898 features). Random forests confirmed their resilience to high dimensionality, as best overall performers on the full data, despite being used in only 4.5% of the surveyed papers. Most other machine learning classifiers were improved by a feature selection filter (ReliefF), but still did not out-perform random forests.

Cytotrophoblast stem cell lines derived from human embryonic stem cells and their capacity to mimic invasive implantation events

BACKGROUND

An effective embryonic-maternal interaction is crucial for successful human pregnancy. Failure of this process is a major cause of infertility and can lead to placental dysfunction resulting in recurrent miscarriage, fetal retardation and pre-eclampsia. Research is severely constrained by ethical and practical considerations; therefore, we aimed to generate cytotrophoblast stem (CTBS) cell lines from human embryonic stem cells (HESCs).

METHOD

Beta-HCG was used as a marker of viable trophoblast cells. In defined culture, embryoid bodies were generated from HESCs and selected for trophoblast enrichment by rounds of cellular aggregation and disaggregation. Distinct CTBS cell lines were isolated and characterized. Spheroid cytotrophoblast bodies were generated and their interaction with luteal-phase endometrial stroma was analysed by real-time image analysis.

RESULTS

Three CTBS cell lines were derived, which were maintained in the absence of residual HESCs, fibroblast feeder cells or extracellular matrix. CTBS cells displayed typical cytotrophoblast and syncytiotrophoblast characteristics and exhibited further differentiation to invasive endovascular cell phenotype. One cell line was generated with constitutive expression of enhanced green fluorescent protein (eGFP). Spheroid trophoblast bodies mimicked closely the early invasive stages of implantation when incubated with human endometrial stromal preparations in vitro.

CONCLUSION

These human CTBS cell lines are a significant new model for investigating human placentation and may have considerable potential in cell therapy applications.

Model-independent source imaging using two-pion correlations in (2 to 8)a GeV Au+Au collisions

We report a particle source imaging analysis based on two-pion correlations in high multiplicity Au+Au collisions at beam energies between 2A and 8A GeV. We apply the imaging technique introduced by Brown and Danielewicz, which allows a model-independent extraction of source functions with useful accuracy out to relative pion separations of about 20 fm. The extracted source functions have Gaussian shapes. Values of source functions at zero separation are almost constant across the energy range under study. Imaging results are found to be consistent with conventional source parameters obtained from a multidimensional Hanburg-Brown-Twiss analysis.

A thaumatin-like gene from Asparagus officinalis (AoPRT-L) exhibits slow activation following tissue maceration or salicylic acid treatment, suggesting convergent defence-related signalling in monocots

Summary Messenger RNA derived from mechanically separated cells of asparagus has proved to be an enriched source of defence-related transcripts. We describe the characterization of a novel PR-5 gene coding for a secreted protein of neutral pI (AoPRT-L) that is strongly up-regulated following cell isolation or following accelerated tissue ageing caused by tissue maceration, but which is also responsive to salicylic acid, a defence-related signal not normally associated with wound responses. Infection with the necrotizing fungal pathogen Stemphylium vesicarium confirmed the responsiveness of AoPRT-L to pathogen challenge in intact plants. An upstream region of the AoPRT-L gene of less than 500 bp was sufficient to confer SA-inducibility in transgenic tobacco. The expression profile of AoPRT-L in both macerated and pathogen challenged tissue suggested there were complex, convergent signalling mechanisms operating during responses to these different stresses.

A PR-5 gene promoter from Asparagus officinalis (AoPRT-L) is not induced by abiotic stress, but is activated around sites of pathogen challenge and by salicylate in transgenic tobacco

Summary Using a promoter-uidA (AoPRT-L-GUS) construct, we have characterized heterologous expression controlled by an Asparagus officinalis acidic PR-5 gene promoter. The construct was found to be up-regulated following a variety of treatments with the defence signal salicylate. Similarly, AoPRT-L-GUS was induced by the SA mimic benzothiodiazole, however, unlike salicylate, this compound does not appear to be transported through the vasculature. The construct was insensitive to wounding and to the wound signal jasmonate. Pathogen challenge resulted in a restricted zone of expression at and around the infection site. High levels of NaCl or PEG 8000 failed to induce foliar expression, however, mannitol proved to be an effective inducer when applied as a root drench. The oxidants H(2)O(2) and t-butyl hydroperoxide also failed to induce AoPRT-L-GUS expression. Developmental expression of the construct appeared to be limited to leaf axils, sepal tips, a proportion of anthers and a small segment of tissue just below the stigma. Thus, the AoPRT-L promoter exhibits a limited expression profile responding principally to salicylate-related defence signals, and shows very little developmental expression. This suggests that the AoPRT-L promoter may be an ideal choice for contained gene expression.

A loss of resistance to avirulent bacterial pathogens in tobacco is associated with the attenuation of a salicylic acid-potentiated oxidative burst

The role of salicylic acid (SA) in events occurring before cell death during the hypersensitive reaction (HR) was investigated in leaves of wild-type tobacco Samsun NN and in transgenic lines expressing salicylate hydroxylase (35S-SH-L). Challenge of 35S-SH-L tobacco with avirulent strains of Pseudomonas syringae gave rise to symptoms resembling those normally associated with a compatible response to virulent strains in terms of visible phenotype, kinetics of bacterial multiplication, and escape from the infection site. Compared with responses in wild-type tobacco, both the onset of plant cell death and the induction of an active oxygen species-responsive promoter (AoPR1-GUS) were delayed following challenge of 35S-SH-L plants with avirulent bacteria. The oxidative burst occurring after challenge with avirulent bacteria was visualized histochemically and quantified in situ. H2O2 accumulation at reaction sites was evident within 1 h after inoculation in wild-type tobacco, whereas in 35S-SH-L plants the onset of H2O2 accumulation was delayed by 2-3 h. The delay in H2O2 generation was correlated with a reduction in the transient rise in SA that usually occurred within 1-2 h following inoculation in wild-type plants. Our data indicate that an early transient rise in SA potentiates the oxidative burst, with resultant effects on accumulation of H2O2, plant cell death and also defence-gene induction, factors that together may determine the outcome of plant-pathogen interactions.

Sideward flow in Au+Au collisions between 2A and 8A GeV

Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au+Au collisions at beam energies of 2A, 4A, 6A, and 8A GeV are presented in the form of in-plane transverse momentum <p(x)> and the first Fourier coefficient of azimuthal anisotropy v(1). These measurements indicate a smooth variation of sideward flow as a function of beam energy. The data are compared with four nuclear transport models which have an orientation towards this energy range. All four exhibit some qualitative trends similar to those found in the data, although none show a consistent pattern of agreement within experimental uncertainties.

Cell-specific expression of salicylate hydroxylase in an attempt to separate localized HR and systemic signalling establishing SAR in tobacco

Abstract There is conflicting evidence concerning the nature of the long-distance signal responsible for establishing the systemic acquired resistance (SAR) state following a local response to an incompatible plant/pathogen interaction. We outline standard inoculation procedures and terminology for experiments used to characterize SAR in Nicotiana tabacum and show that leaf development (age) has dramatic affects on TMV lesion size which needs to be taken into account in experimental design. TMV infection was more efficient at inducing SAR than primary infection with avirulent bacteria. We have examined the effect on SAR induction of altering the accumulation of salicylic acid (SA), through the expression of a salicylate hydroxylase gene (SH-L), in different phases of lesion development using the hydrogen peroxide-responsive AoPR1 promoter and the salicylate-responsive PR1a promoter. Suppression of SA accumulation during the early phases of lesion development in AoPR1-SH-L transgenic tobacco resulted in an attenuated form of SAR compared to wild-type plants, whereas SAR was not exhibited in PR1a-SH-L plants. However, interpretation of data from these experiments was complicated by virus escape from inoculated leaves. Using a GUS reporter it was discovered that the CaMV35S promoter was not expressed constitutively in all cell types of petioles and stems, particularly phloem tissue, whereas the PR1a promoter demonstrated induced expression in the phloem following TMV infection. We suggest two hypotheses for why PR1a-SH-L transgenics do not display SAR: either the systemic expression of PR1a-SH-L is sufficient to suppress SAR, or SA synthesis or translocation in the phloem is essential for SAR.

Compromising early salicylic acid accumulation delays the hypersensitive response and increases viral dispersal during lesion establishment in TMV-infected tobacco

To investigate the role of salicylic acid (SA) in the hypersensitive response (HR) its accumulation was compromised during different phases of lesion development by differential expression of a salicylate hydroxylase gene (SH-L). Constitutive suppression of SA accumulation was achieved by expression of a gene fusion between the CaMV35S promoter (35S) and SH-L. Using the H2O2-responsive AoPR1 promoter to drive SH-L SA accumulation could be compromised at an early stage, on lesion formation and possibly prior to visible necrosis, whilst use of the salicylate-responsive PR1a promoter reduced SA accumulation at a later stage as lesions expand. TMV infection of 35S-SH-L and AoPR1-SH-L, but not PR1a-SH-L, tobacco resulted in significantly greater rates of lesion growth than in wild-type tobacco. TMV was detected in asymptomatic tissue surrounding lesions only in 35S-SH-L and AoPR1-SH-L lines; subsequently these transgenic lines exhibited a 'spreading-necrosis' originating from the lesion which entered the stem and eventually other leaves, a phenotype which could be correlated with the presence of TMV particles. Analysis of TMV-infected and 'temperature-shifted' tobacco indicated that both 35S-SH-L and AoPR1-SH-L, but not PR1a-SH-L, transgenics exhibited delayed cell-death compared to wild-type infections. We propose that the SH-L phenotypes indicate that early SA accumulation is a major factor in preventing viral escape, via mechanism(s) which may include influencing the rate of host-cell death and, possibly, an effect on viral function.

Whose welfare in the labour room? A discussion of the increasing trend of fathers' birth attendance

OBJECTIVE

To review the key literature on fathers' birth attendance, discussing: factors contributing to the increasing trend in men's birth attendance; the different roles and responsibilities men may adopt in the labour room and the implications; and, particularly, the education needs of both the expectant fathers and the professionals.

LITERATURE SEARCH

The literature reported here is part of a larger longitudinal ethnographic study of men's experiences of pregnancy and birth, which to date has generated 190 relevant articles. The literature was identified using: the Midwifery Information Resource Service (MIDIRS), PsychLit, Cinahl, Medline, and the Cochrane Pregnancy and Childbirth Database. Keywords were: men, fathers, pregnancy, birth, and birth supporters. Literature was also identified using references quoted in papers and hand searching of journals.

KEY CONCLUSIONS

Changing cultural and professional attitudes have encouraged fathers' birth attendance, reflected in an increasing volume of research. This research concentrates almost exclusively on labour coaching roles, neglecting exploration of any independent needs men may have.

IMPLICATIONS FOR PRACTICE

A greater awareness of men's experiences will inform midwives and childbirth educators to effectively provide for men's needs during pregnancy and birth.

Alternative processing of the maize Ac transcript in Arabidopsis

The successful application of the maize transposable element system Ac/Ds as a genome mutagen in heterologous plant species has recently proved the versatility and power of this technique in plant molecular biology. However, the frequency of Ac/Ds transposition is considerably lower in Arabidopsis thaliana than in most other dicot plant species that have been studied. Since previous research has established that transcripts derived from monocot genes can be alternatively processed in dicot plants, we have investigated both the efficiency of intron splicing and polyadenylation of the maize Ac transposase pre-mRNA in Arabidopsis thaliana, Nicotiana tabacum, Nicotiana plumbaginifolia and Zea mays. In this paper, we demonstrate that intron 4 is alternatively spliced within Arabidopsis, using cryptic 5' and 3'splice sites within the intron sequence, leading to a heterogeneous population of full length of transposase transcript. Furthermore, analysis of transposase transcript polyadenylation revealed that at least four alternative poly(A) sites were utilized between introns 2 and 3, resulting in truncated transposase transcripts. Finally, by Northern blotting, we established that the truncated transposase transcript was the most abundant form of transposase message in Arabidopsis. In contrast to these findings, the alternative splicing and premature polyadenylation of Ac message in Arabidopsis was unparalleled in the other species examined. We suggest that the poor frequency of transposition of Ac in Arabidopsis may be in part due to the low quantity of correctly processed transposase transcript available in this species.

A discussion of some of the literature relating to history, repair and consequences of perineal trauma

OBJECTIVE

to review the key literature on perineal trauma, discussing the historical background, the materials and techniques used, the possible consequences of repair and assess midwives' current and potential contribution to perineal repair.

LITERATURE SEARCH

the literature was identified using conventional search techniques: Midwifery Information Resource Service (MIDIRS) and the Cochrane Pregnancy and Childbirth Database. Keywords used during the search were: episiotomy, perineal trauma and adverse effects. Associated keywords words were sexuality, pain and psychology.

KEY CONCLUSIONS

current practice in the UK is inconsistent with the available evidence, perineal trauma can cause long term problems, and midwives are in an ideal position to take forward evidence-based perineal repair.

IMPLICATIONS FOR PRACTICE

midwives need adequate education and training in perineal repair but are likely to be more effective in performing the repair. Systematic evaluation of the impact of extending midwives' influence in this area is essential.

An investigation into the application and maintenance of Hamilton Russell traction on three orthopaedic wards

This study is concerned with the application and maintenance of Hamilton Russell traction, a form of vectored skin traction. It may be used in the treatment of fractures of the femur for the purposes of immobilization and for pain relief prior to surgery. A preliminary questionnaire demonstrated a poor level of knowledge in nurses working in an orthopaedic area. It was therefore speculated that application and maintenance of the traction would be inaccurate. The angles making up the resultant traction forces were measured in 11 systems. The theoretical traction force was established using mathematics. The actual force was measured using a goniometer. A comparison was then made. The results in all 11 systems demonstrated a highly statistically significant difference between the theoretical and actual positions of the traction force (P < 0.0005). The practical implications of this are discussed and recommendations for a protocol of application and maintenance suggested. Areas for further research are identified.

Nursing development units: an opportunity for evaluation

The nursing development unit movement has recently generated a lot of financial and professional interest. This is demonstrated by the large financial investment by the Department of Health, England, and the growing number of papers in the nursing literature. The benefits of these units, however, are not as well documented. This paper seeks to contribute to the debate by: reviewing some of this literature and putting the movement in a historical perspective; discussing the purposes of the units; critically examining the characteristics of such units; evaluating their effectiveness; and suggesting a way forward for the future.

Hydrogen peroxide does not function downstream of salicylic acid in the induction of PR protein expression

The roles of salicylic acid (SA) and H2O2 in the induction of PR proteins in tobacco have been examined. Studies were conducted on wild-type tobacco and plants engineered to express a bacterial salicylate hydroxylase capable of metabolizing SA to catechol (SH-L plants). Wild-type and PR-1a-GUS-transformed plants express PR-1a following challenge with Pseudomonas syringae pathovar syringae, SA or 2,6-dichloro-isonicotinic acid (INA). In contrast, SH-L plants failed to respond to SA but did express PR-1a following INA treatment. H2O2 and the irreversible catalase inhibitor 3-amino-1,2,4-triazole (3-AT) were found to be weak inducers of PR-1a expression (relative to SA) in wild-type tobacco but were unable to induce PR-1a in SH-L plants, suggesting that the action of these compounds depends upon the accumulation of SA. A model has been proposed suggesting that SA binds to and inhibits a catalase inducing an increase in H2O2 leading to PR protein expression. Catalase activity has been measured in tobacco and no significant changes in activity following infection with P. syringae pv. syringae were detected. Furthermore, inhibition of catalase activity in vitro in plant extracts requires pre-incubation and only occurs at SA concentrations above 250 microM. Leaf disks preincubated with 1 mM SA do accumulate SA to these levels and PR-1a is efficiently induced but there is no apparent inhibition of catalase activity. It is also shown that a SA-responsive gene, PR-1a, and a H2O2-sensitive gene, AoPR-1, are both relatively insensitive to 3-AT suggesting that induction of these genes is unlikely to be due entirely to inhibition of an endogenous catalase.

Risk factors for recurrent emergency department visits for asthma

BACKGROUND

Patients presenting with asthma to emergency departments have lost control of their disease, have significant airways obstruction, and frequently require admission to hospital. Although even one visit is not desirable, there is a more disturbing subgroup who repeatedly visit the emergency department.

METHODS

To investigate the reasons for multiple emergency visits, a questionnaire was given to 448 consecutive patients presenting to the two largest adult emergency departments in Ottawa, Canada between November 1989 and April 1991. Within this cohort, those who had made at least three visits in the past year were compared with controls (only one visit in the past year).

RESULTS

Although inhaled corticosteroid use increased with multiple visits (indicating increased asthma severity), only 60% of those visiting at least three times in the past year were taking inhaled corticosteroids. Chronic undermedication relative to disease severity was apparent among the cases. The number of visits was associated with nocturnal asthma on a regular basis, work and school absenteeism, frequent visits to their regular physician, and frequent admissions to hospital. Visits were not related to psychological health, environmental allergens/irritants, or lack of perceived asthma severity.

CONCLUSIONS

The recommendations of current asthma guidelines are not reaching these patients. The issue of translating guidelines from paper to practice must be addressed before highly effective medications can have an important impact on the frequency of emergency department visits.

Outcome of patients after air medical transport for management of nontraumatic acute intracranial bleeding

INTRODUCTION

Patients with acute, intracranial bleeding (ICB), particularly from intracranial aneurysms, are believed to be at high risk for rebleeding or neurologic deterioration if subjected to noise, motion, or stress, but are transported by helicopter with increasing frequency. This study was undertaken to examine the characteristics, safety, and outcomes of air transport for patients with acute subarachnoid hemorrhage (SAH) or other forms of acute ICB in an air medical system.

METHODS

Charts of all patients with spontaneous, acute ICB who were transported by air from 1986 through 1989 were reviewed. Age, gender, time of transport, transport management measures, pre- and post-transport Glasgow Coma Scale (GCS) score, intensive care unit (ICU) and hospital days, operations, and mortality were compiled for all patients and analyzed.

RESULTS

Eighty-seven patients ranging in age from 2 to 83 years (mean: 47.5 +/- 18.5 years) met entry criteria. The source of bleeding was cerebral aneurysm in 37 patients; intraparenchymal hemorrhage in 29; an unidentified vascular source in 11; and arteriovenous malformation (AVM) in 10. Mean GCS score measured in 69 patients before and after transport was 10.5 +/- 4.5 Glasgow Coma Scale score did not change during transport in 61 patients (88%), improved in three (4%), and deteriorated in five (7%). Fifty-nine patients (69%) underwent operations, 36 (41%) within 24 hours of arrival. Mean ICU stay was 14 days (95% CI: 12-15); mean hospital stay was 36 days (95% CI: 27-45 days). Overall mortality was 25% (95% CI: 16-34 days). A GCS score of 3 to 8 at time of transport was associated with both increased hospital length of stay and higher mortality. Patients transported within eight hours of symptom onset had lower GCS scores, but outcome measures were not significantly different from those transported later.

CONCLUSIONS

Emergency air medical transfer of patients with acute ICB for definitive neurosurgical care appears to be both safe and effective, and facilitates early definitive diagnosis and operative intervention.

Endoplasmic reticulum targeting of active modified beta-glucuronidase (GUS) in transgenic tobacco plants

We have investigated targeting to the endoplasmic reticulum (ER) of wild-type GUS and a modified form (GUS S358) by making an N-terminal fusion of the beta-glucuronidase (GUS) enzyme with the wheat alpha-amylase signal peptide. In vitro studies demonstrated that the modified GUS (S358) lacked the glycosylation site present within the wild-type enzyme. Analysis of transgenic tobacco plants revealed that the modified GUS enzyme retained activity upon passage to the ER. When further experiments were carried out to determine the cellular location of the modified GUS enzyme, it was found that (contrary to expectation) the majority of GUS activity was retained within the cell and was not secreted to the cell surface via the default pathway. The data indicated that the modified GUS enzyme is an unsuitable reporter enzyme for studying protein secretion.

The developmental expression of the asparagus intracellular PR protein (AoPR1) gene correlates with sites of phenylpropanoid biosynthesis

Previous reports have described the induction, by either wounding or attempted pathogen invasion, of an Asparagus officinalis intracellular pathogenesis-related (AoPR1) promoter-GUS gene fusion in transgenic tobacco. Here we describe the unexpected developmental expression pattern of the AoPR1-GUS gene which correlates well, temporally and spatially, with the developmental expression observed for GUS fusions with promoters derived from genes coding for enzymes in the 'core phenylpropanoid pathway'. Analysis of endogenous AoPR1 gene expression in asparagus and both AoPR1-GUS and AoPR1-luciferase gene fusions in transgenic tobacco suggests that the AoPR1 promoter directs similar cell-specific transcription patterns in both asparagus and transgenic tobacco. The AoPR1 promoter contains sequence motifs similar to those implicated as important in the regulation of phenylpropanoid pathway genes and another 'intracellular' PR gene. Treatment with salicylic acid enhances AoPR1 promoter gene activity both in tobacco and in asparagus.

Secretion of a functional single-chain Fv protein in transgenic tobacco plants and cell suspension cultures

A synthetic gene encoding an anti-phytochrome single-chain Fv (scFv) antibody bearing an N-terminal signal peptide has been used to transform tobacco plants. Immunoblot analysis showed that transformed plants accumulate high levels of scFv protein, accounting for up to 0.5% of the total soluble protein fraction, which could be extracted by simple infiltration and centrifugation of leaf tissue. A substantial proportion of the scFv protein extracted in this way was found to possess antigen-binding activity. Callus cell suspension cultures derived from transformed plants secrete functional scFv protein into the surrounding medium. Compared with the levels of scFv protein observed in plants expressing the native scFv gene, the incorporation of an N-terminal signal peptide, to target the scFv to the apoplast, results in elevated accumulation of the protein.

Characterization of a new class of oleosins suggests a male gametophyte-specific lipid storage pathway

The expression and sequences of two related antherspecific cDNAs (I3 and C98) of Brassica napus (oilseed rape) were examined. These cDNAs were found to exhibit significant predicted amino acid sequence similarity with a group of seed-specific proteins, the oleosins, which are involved in oil body membrane structure. Pollen of B. napus also contains oil bodies, and the synthesis and accumulation of these organelles correlates with expression of the I3 and C98 transcripts. The protein content of purified pollen oil bodies was therefore examined in order to determine the presence or absence of possible oleosins. One major protein species of 14 kDa was identified and subjected to N-terminal amino acid sequence determination. The sequence of this pollen oil body associated protein is homologous to the predicted sequence of one of the anther-specific cDNs, I3, implying that this cDNA represents an anther-specific oleosin gene expressed in developing pollen. The expression of other genes active during seed oil body formation was also examined, and these were found to be specific to the sporophyte, inferring the existence of specific components of the pathway of lipid synthesis and storage in the male gametophyte. These possibilities and the relationship between different oleosin genes are discussed.

A wound-induced promoter driving npt-II expression limited to dedifferentiated cells at wound sites is sufficient to allow selection of transgenic shoots

There is much data to indicate that only a small number of cells in plant explants are competent for stable transformation by Agrobacterium. Circumstantial evidence suggests that certain cells reentering cell division at wound sites are competent for transformation by Agrobacterium. We have discovered a member of the intracellular PR gene family from asparagus (AoPR1) which is strongly expressed upon wounding and during the reactivation of the cell cycle in cultured asparagus cells, but which shows very little expression in intact plant tissues. The promoter from the AoPR1 gene was fused to an intron-containing GUS reporter gene and shown to be more strongly expressed than the commonly used CaMV 35S constitutive promoter in target cells for plant transformation. A transcriptional fusion of the AoPR1 promoter with an NPT-II gene was found to be a very efficient marker for the selection of transgenic tobacco callus. Expression of the AoPR1-NPT-II gene allowed efficient shoot formation on transgenic callus and efficient adventitious root formation on transgenic shoots. These latter observations provided firm evidence that transformation selection marker gene expression is most crucial at the early stages of the transformation process, during the establishment of transformed micro-calli.

Isolation of an asparagus intracellular PR gene (AoPR1) wound-responsive promoter by the inverse polymerase chain reaction and its characterization in transgenic tobacco

The Asparagus officinalis intracellular PR1 (AoPR1) gene is expressed in response to wounding and pathogen attack. We utilized the inverse polymerase chain reaction (IPCR) to isolate the cis-acting regulatory sequences of the AoPR1 gene following unsuccessful attempts to identify hybridizing clones in genomic libraries. Sequence analysis of two IPCR products revealed that a 347 bp intron was present in the AoPR1 gene and that it was probable that the AoPR1 regulatory sequence had been amplified. To test the AoPR1 cis-acting sequences for biological function a translational fusion was constructed with the beta-glucuronidase (GUS) reporter gene and tested in tobacco. These data demonstrated that sequences 982 bp from the probable start of transcription are sufficient to direct wound-inducible transcription and that there is no signal peptide encoded by the first 31 residues of the predicted AoPR1 protein. Histochemical localization of GUS activity in transgenic tobacco demonstrated strong activity localized to wound and pathogen invasion sites. GUS activity was also found in mature pollen grains.

Gametophytic and sporophytic expression of an anther-specific Arabidopsis thaliana gene

Genomic and cDNA clones of the anther-specific APG gene from Arabidopsis thaliana and Brassica napus, which encodes a novel proline-rich protein, were isolated and characterized. Southern blotting and Northern analysis of male fertile and cytoplasmic male sterile varieties of B. napus showed that the APG gene is present as a single copy in the Arabidopsis genome, and that the B. napus APG gene is a member of a small anther-specific gene family. Analysis of developmentally staged B. napus flower buds indicated that APG transcript is confined to the anther during the period of microspore development. Reporter gene fusions established that the APG promoter directs expression in a number of cell types in anthers of transformed plants. This expression is consistent with the temporal pattern of mRNA accumulation in B. napus buds and follows a complex developmental pattern. Most significantly, the promoter is active in both sporophytic and gametophytic cell types, with activity of the transgene in each cell type being delineated by various cytological markers.

Expression of Helenium virus S coat protein in Escherichia coli, in vitro in rabbit reticulocyte lysate and transgenic tobacco

The coat protein open reading frame (ORF) sequence of Helenium virus S (HelVS) was cloned and expressed in E. coli, rabbit reticulocyte and transgenic tobacco. In E. coli the size of the protein was identical to that obtained for the coat protein from purified virus particles and less than that predicted for the fusion protein. This may be due to ribosome binding at a potential ribosome binding site present on the viral sequence, approximately 45 nucleotides upstream from the initiating methionine of the coat protein ORF. This region of HelVS, equivalent to the 1.5 kb subgenomic RNA, also produced high levels of protein when transcribed and translated in vitro. When introduced into Nicotiana tabacum by leaf disk transformation via Agrobacterium tumefaciens, high levels of stable coat protein were detected which were identical in molecular weight to that of HelVS coat protein and constituted approximately 0.1-0.5% of the total extracted protein.

Chloroplast Dedifferentiation in Mechanically Isolated Asparagus Cells during Culture Initiation

Mechanically isolated asparagus (Asparagus officinalis) mesophyll cells dedifferentiate and divide when cultured in the dark in a medium containing sucrose. A strong correlation was observed between the onset of cell division and a loss of photosynthetic capacity. For the first 8 to 9 d of culture, there was no change in chloroplast size or morphology. However, following this period, the chloroplasts divided to form smaller proplastid-like structures. The gross chlorophyll content of the cell population did not change, suggesting that the loss of photosynthetic potential was not by senescence. Northern analysis showed that mRNA of the small subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase was undetectable within 1 d postisolation, which was quicker than in dark-treated plants. The mRNA of the large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase decreased to low levels within 2 d of cell isolation. Both the large and small subunits of ribulose 1,5-bisphosphate carboxylase/oxygenase protein showed a gradual reduction in abundance, falling to basal levels by days 6 to 7, which coincided with the onset of rapid cell division. A similar trend was observed with chloroplast rRNA molecules, which decreased to basal levels by day 6 in culture.

The isolation and characterisation of the tapetum-specific Arabidopsis thaliana A9 gene

The Brassica napus cDNA clone A9 and the corresponding Arabidopsis thaliana gene have been sequenced. The B. napus cDNA and the A. thaliana gene encode proteins that are 73% identical and are predicted to be 10.3 kDa and 11.6 kDa in size respectively. Fusions of an RNase gene and the reporter gene beta-glucuronidase to the A. thaliana A9 promoter demonstrated that in tobacco the A9 promoter is active solely in tapetal cells. Promoter activity is first detectable in anthers prior to sporogenous cell meiosis and ceases during microspore premitotic interphase. The deduced A9 protein sequence has a pattern of cysteine residues that is present in a superfamily of seed plant proteins which contains seed storage proteins and several protease and alpha-amylase inhibitors.

Premature dissolution of the microsporocyte callose wall causes male sterility in transgenic tobacco

Male sterility in a petunia cytoplasmic male sterile line has been attributed to the early appearance of active callase, a beta-1,3-glucanase, in the anther locule. This leads to premature dissolution of the callose walls surrounding the microsporogenous cells. We have mimicked this aspect of the petunia line in transgenic tobacco by engineering the secretion of a modified pathogenesis-related vacuolar beta-1,3-glucanase from the tapetum prior to the appearance of callase activity in the locule. Plants expressing the modified glucanase from tapetum-specific promoters exhibited reduced male fertility, ranging from complete to partial male sterility. Callose appearance and distribution are normal in the male sterile transgenic plants up to prophase I, whereupon callose is prematurely degraded. Meiosis and cell division occur normally. The resultant microspores have an abnormally thin cell wall that lacks sculpturing. The tapetum shows hypertrophy. Male sterility is probably caused by bursting of the aberrant microspores at a time corresponding to microspore release. These results demonstrate that premature callose degradation is sufficient to cause male sterility and suggest that callose is essential for the formation of a normal microspore cell wall.

High frequency adventitious shoot regeneration from immature cotyledons of pea (Pisum sativum L.)

A procedure has been developed which allows high frequency adventitious shoot regeneration from immature cotyledons of pea. Prolific shoot regeneration occurred following an initial callus growth on a Murashige and Skoog (MS) medium containing 0.5 mg/l 6-benzylaminopurine (BAP) and 4 mg/l α-naphthaleneacetic acid (NAA). Cotyledon expiants proximal to the embryonic axis had the highest regeneration potential, however, the presence of an embryonic axis inhibited adventitious shoot regeneration. Addition of silver nitrate (AgNO3) to the medium did not promote the number of regenerated shoots but resulted in shoots with well developed tendrils and large stipules which had a reduced rooting capacity. Regenerated shoots rooted readily (80-90%) in half strength MS medium containing 1 mg/l indole-butyric acid (IBA) and further established well in compost.