Glucose-6-phosphate dehydrogenase and 8-iso-prostaglandin F2α as potential predictors of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Delayed cerebral ischemia (DCI) is a serious complication of aneurysmal subarachnoid hemorrhage (aSAH), which is responsible for significant death and disability. The dynamic balance between the production and elimination of reactive oxygen species (ROS) in patients with DCI is suspected be shifted to favor ROS formation. The authors assessed the relationship between F2-isoprostanes (F2-IsoPs), oxidative stress biomarkers, and glucose-6-phosphate dehydrogenase (G6PD), which are responsible for nicotinamide adenine dinucleotide phosphate (NADPH) production for glutathione system function, with post-aSAH DCI.

METHODS

The authors assessed 45 aSAH patients for F2-IsoP and G6PD concentration using commercial ELISA on days 2, 4, and 6 after aSAH. The authors examined the correlation between plasma F2-IsoP and G6PD concentrations and clinical factors with DCI occurrence and aSAH outcome.

RESULTS

Expectedly, the most important clinical predictors of DCI were Hunt and Hess grade and modified Fisher (mFisher) grade. Plasma F2-IsoP and G6PD concentrations were greater in aSAH patients than the control group (p < 0.01). F2-IsoP concentrations were greater and G6PD concentrations were lower in patients with DCI than those without (p < 0.01). Plasma F2-IsoP and G6PD concentrations on day 2 were correlated with DCI occurrence (p < 0.01). Plasma F2-IsoP concentrations on days 2 and 6 were correlated with outcome at 1 and 12 months (p < 0.01).

CONCLUSIONS

Decreased G6PD indirectly informs the reduced antioxidant response, especially for the glutathione system. G6PD concentration was lower in patients with DCI than those without, which may explain the increased F2-IsoP concentrations. mFisher grade, plasma F2-IsoP concentration, and G6PD concentration on day 2 after aSAH, in combination, may serve as predictors of DCI. Further research is necessary to investigate the therapeutic utility of F2-IsoPs and antioxidants in clinical practice.

Orbito-cranial schwannoma-a multicentre experience

OBJECTIVES

To describe the features, management approaches, and outcomes of orbito-cranial schwannomas.

METHODS

Retrospective review of ten patients with orbito-cranial schwannomas managed in six orbital services over 22 years. Data collected included demographics, presenting features, neuroimaging characteristics, histology, management approach, complications, and outcomes.

RESULTS

Mean age of the patients was 41.4 ± 19.9 years, and 6 (60%) were females. The majority presented with proptosis (90%), limited extraocular motility (80%), eyelid swelling (60%), and optic neuropathy (60%). Most lesions (80%) involved the entire anterior-posterior span of the orbit, with both intra- and extraconal involvement. All tumours involved the orbital apex, the superior orbital fissure, and extended at least to the cavernous sinus. Surgical resection was performed for all. Seven (70%) of the tumours were completely or subtotally resected combining an intracapsular approach by an orbital-neurosurgical collaboration, with no recurrence on postoperative follow-up (6-186 months). Three underwent tumour debulking. Of these, two remained stable on follow-up (6-34 months) and one showed progression of the residual tumour over 9 years (cellular schwannoma on histology) necessitating stereotactic radiotherapy (SRT) for local control. Adjuncts to the orbito-cranial resection included perioperative frozen section (n = 5), endoscopic transorbital approach (n = 2), and image-guided navigation (n = 1). Post-surgical adjuvant SRT was used in three subjects.

CONCLUSIONS

These results highlight the possibility of successful surgical control in complex orbito-cranial schwannomas. A combined neurosurgical/orbital approach with consideration of an intracapsular resection is recommended. Recurrence may not occur with subtotal excision and observation may be reasonable. Adjunctive SRT for progression or residual tumour can be considered.

Comparative proteomic analysis of ventricular and cisternal cerebrospinal fluid in haemorrhagic stroke patients

BACKGROUND

Analysis of cerebrospinal fluid (CSF) using mass spectrometry is a relatively novel analytical tool, and comparisons of ventricular and cisternal proteomes are yet to be performed. This may have implications for clinical medicine, particularly in demonstrating continuity of the ventricular system with preserved flow in the presence of ventricular blood. Other uses include the identification of novel biomarkers, including for diagnosis of subarachnoid haemorrhage and of aetiology. The primary objective was therefore to characterise and compare the proteomes of ventricular and CSF after haemorrhagic stroke.

METHODS

Paired CSF samples were prospectively collected from the optico-carotid cistern and the frontal horn of the lateral ventricle at the time of craniotomy and clipping in 8 patients with haemorrhagic stroke. Six patients had an aneurysmal subarachnoid haemorrhage (aSAH) from a ruptured saccular aneurysm, one patient had an aSAH after rupture of a mycotic aneurysm and one patient had a spontaneous intracerebral haemorrhage (IPH) with an adjacent unruptured saccular aneurysm. Samples were processed and proteins identified and quantified using data-dependent liquid chromatography tandem mass spectrometry (DDA LC-MSMS).

RESULTS

There was no systematic difference between the cisternal and ventricular proteomes. However, blinded principal component analysis (PCA) of the cisternal and ventricular samples separated patients according to pathophysiology. Additionally CSF D-Dimer levels were not detected in the IPH patient but were reliably measured in aSAH patients.

CONCLUSIONS

Ventricular CSF is representative of cisternal CSF after aSAH. CSF proteomic PCA analysis can distinguish between haemorrhage types. CSF D-dimer levels may represent a novel diagnostic marker for aSAH. Label free DDA LC-MSMS CSF analysis may inform possible biomarkers.

What you sample is what you get: ecomorphological variation in Trithemis (Odonata, Libellulidae) dragonfly wings reconsidered

Background

The phylogenetic ecology of the Afro-Asian dragonfly genus Trithemis has been investigated previously by Damm et al. (in Mol Phylogenet Evol 54:870–882, 2010) and wing ecomorphology by Outomuro et al. (in J Evol Biol 26:1866–1874, 2013). However, the latter investigation employed a somewhat coarse sampling of forewing and hindwing outlines and reported results that were at odds in some ways with expectations given the mapping of landscape and water-body preference over the Trithemis cladogram produced by Damm et al. (in Mol Phylogenet Evol 54:870–882, 2010). To further explore the link between species-specific wing shape variation and habitat we studied a new sample of 27 Trithemis species employing a more robust statistical test for phylogenetic covariation, more comprehensive representations of Trithemis wing morphology and a wider range of morphometric data-analysis procedures.

Results

Contrary to the Outomuro et al. (in J Evol Biol 26:1866–1874, 2013) report, our results indicate that no statistically significant pattern of phylogenetic covariation exists in our Trithemis forewing and hindwing data and that both male and female wing datasets exhibit substantial shape differences between species that inhabit open and forested landscapes and species that hunt over temporary/standing or running water bodies. Among the morphometric analyses performed, landmark data and geometric morphometric data-analysis methods yielded the worst performance in identifying ecomorphometric shape distinctions between Trithemis habitat guilds. Direct analysis of wing images using an embedded convolution (deep learning) neural network delivered the best performance. Bootstrap and jackknife tests of group separations and discriminant-function stability confirm that our results are not artifacts of overtrained discriminant systems or the “curse of dimensionality” despite the modest size of our sample.

Conclusion

Our results suggest that Trithemis wing morphology reflects the environment’s “push” to a much greater extent than phylogeny’s “pull”. In addition, they indicate that close attention should be paid to the manner in which morphologies are sampled for morphometric analysis and, if no prior information is available to guide sampling strategy, the sample that most comprehensively represents the morphologies of interest should be obtained. In many cases this will be digital images (2D) or scans (3D) of the entire morphology or morphological feature rather than sparse sets of landmark/semilandmark point locations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12862-022-01978-y.

Life after surgical resection of a low-grade glioma: A prospective cross-sectional study evaluating health-related quality of life

Health related quality of life (HRQoL) has become an important consideration in LGG patients. We report the largest prospective, longitudinal, cross-sectional cohort study of HRQoL in LGG patients, aiming to identify actionable determinants of HRQoL. Post-operative LGG adults at a large tertiary center underwent HRQoL assessment using the EORTC QLQ-C30 questionnaire administered at follow-up visits and by mail. Scores at 12 month intervals were compared with those from a normative reference population. Spearman's Rho was used to evaluate correlation of subdomain and symptom scores with global HRQoL and change over time. There were 167 participants and 366 questionnaires analysed. Patients reported reduced global HRQoL at nearly every 12 month interval with significant impairments at 12, 72, 108, and 120+ months postoperative. They also reported a significant impairment in each functional subdomain at 12 months, which persisted to varying degrees over 120 months, as did significant fatigue and insomnia. Role, emotional, and social subdomains, as well as fatigue, were significantly associated with global HRQoL at the first 12 month interval. Overall, there was no significant correlation between time from surgery and global HRQoL or the subdomain functional or symptom sections of the QLQ-C30. LGG patients report considerable, sustained impairments in HRQoL after surgery, particularly in cognitive, emotional, and social function, as well as suffering significant fatigue and insomnia. These are strongly associated with global HRQoL and thus can be considered determinants of global HRQoL that with intervention, may improve HRQoL for our LGG patients. This is the largest prospective longitudinal study of HRQoL in postoperative LGG patients yet reported and is ongoing. It identifies several determinants of impaired HRQoL with available management options and interventions that have the potential to significantly improve HRQoL in these patients.

Life after surgical resection of a meningioma: a prospective cross-sectional study evaluating health-related quality of life

Background

Few studies have evaluated the health-related quality of life (HRQoL) of patients with meningiomas. Here, we report the largest prospective, longitudinal cross-sectional cohort study of HRQoL in meningiomas to date, in order to identify possible actionable determinants of global HRQoL.

Methods

Adults who had undergone resection of a grade I intracranial meningioma and were in routine follow-up at a single large tertiary center underwent HRQoL assessment using the QLQ-C30 questionnaire administered opportunistically at follow-up visits. Averaged transformed QLQ-C30 scores at 12-month intervals were compared with scores from a normative reference population, with reference to known minimal clinically meaningful difference (CMD) in scores. To evaluate for possible determinants of changes in global HRQoL, global HRQoL scores were correlated (Spearman's Rho) with subdomain and symptom scores and with interval time from surgical resection.

Results

A total of 291 postoperative patients with histologically confirmed and surgically treated grade I meningiomas consented to participation and a total of 455 questionnaires were included for analysis. Patients with meningiomas reported reduced global HRQoL at nearly every 12-month interval with clinically and statistically significant impairments at 12, 48, 108, and 120 months postoperative compared with the normative population (P < 0.05). Meningioma patients at the 12-month interval also reported a reduction of each subdomain of HRQoL assessment (P < 0.05); however, a CMD was only seen in cognitive functioning. Physical, emotional, cognitive, and social subdomains, as well as fatigue and sleep/insomnia, were significantly associated with global HRQoL at the first 12-month interval. Overall, there was no significant correlation between time from surgery and global HRQoL or the subdomain functional or symptom sections of the QLQ-C30.

Conclusions

Meningioma patients report considerable limitations in HRQoL for more than 120 months after surgery, particularly in cognitive, emotional, and social function, as well as suffering significant fatigue and sleep impairment compared with a normative reference population. The majority of these reported functional impairments and symptoms are strongly associated with global HRQoL and thus can be considered determinants of global HRQoL that if treated, have the potential to improve HRQoL for our meningioma patients. This hypothesis requires future study of targeted interventions to determine their efficacy.

Ahead of the curve: three approaches to mass digitisation of vials with a focus on label data capture

There has been little research on novel approaches to digitising liquid-preserved natural history specimens stored in jars or vials. This paper discusses and analyses three different prototypes for high-throughput digitisation using cheap, readily available components. This paper has been written for other digitisation teams or curators who want to trial or improve upon these new digitisation approaches in liquid preserved collections.

Advancing the use of molecular methods for routine freshwater macroinvertebrate biomonitoring – the need for calibration experiments

Over the last decade, steady advancements have been made in the use of DNA-based methods for detection of species in a wide range of ecosystems. This progress has culminated in molecular monitoring methods being employed for the detection of several species for enforceable management purposes of endangered, invasive, and illegally harvested species worldwide. However, the routine application of DNA-based methods to monitor whole communities (typically a metabarcoding approach) in order to assess the status of ecosystems continues to be limited. In aquatic ecosystems, the limited use is particularly true for macroinvertebrate communities. As part of the DNAqua-Net consortium, a structured discussion was initiated with the aim to identify potential molecular methods for freshwater macroinvertebrate community assessment and identify important knowledge gaps for their routine application. We focus on three complementary DNA sources that can be metabarcoded: 1) DNA from homogenised samples (bulk DNA), 2) DNA extracted from sample preservative (fixative DNA), and 3) environmental DNA (eDNA) from water or sediment. We provide a brief overview of metabarcoding macroinvertebrate communities from each DNA source and identify challenges for their application to routine monitoring. To advance the utilisation of DNA-based monitoring for macroinvertebrates, we propose an experimental design template for a series of methodological calibration tests. The template compares sources of DNA with the goal of identifying the effects of molecular processing steps on precision and accuracy. Furthermore, the same samples will be morphologically analysed, which will enable the benchmarking of molecular to traditional processing approaches. In doing so we hope to highlight pathways for the development of DNA-based methods for the monitoring of freshwater macroinvertebrates.

Improving the competency of medical students in clinical breast examination through a standardized simulation and multimedia-based curriculum

PURPOSE

Clinical breast examination (CBE) is an important step in the assessment of patients with breast-related complaints. We developed a standardized simulation and multimedia-based (SSMBI) curriculum using current evidenced-based recommendations. This study aimed to determine if SSMBI training resulted in better performance (examination scores and detection of abnormal findings) than the traditional teaching method.

METHODS

Novice fourth-year medical students were exposed to the SSMBI curriculum (n = 68) or traditional (n = 52) training. The traditional group was taught by a lecture and attending weekly clinics where they had hands-on experience. The SSMBI group underwent a structured lecture followed by an instructional video and dedicated simulated teaching. Both groups were assessed through a written knowledge exam and an objective structured clinical examination (OSCE). Student's t test and χ² tests were used to assess differences in CBE technique and knoweldge.

RESULTS

Students who underwent SSMBI training had significantly higher numbers of correct answers describing the different steps and justifications of CBE. OSCE performance was significantly higher in the SSMBI group. SSMBI-trained students were more likely to complete all the necessary CBE steps compared to traditionally-trained students (88.2% vs. 28.2%, p < 0.00001). The SSMBI group was also more systematic and more likely to perform adequate inspection, palpation, examination of the nipple-areolar complex, and identify and characterize a palpable lesion (p < 0.05).

CONCLUSIONS

Formal SSMBI training is an important asset when teaching medical students how to perform a CBE. Real clinical experience is still necessary to refine this skill and the physician-patient interaction.

Tree biomass in the Swiss landscape: nationwide modelling for improved accounting for forest and non-forest trees

Trees outside forest (TOF) can perform a variety of social, economic and ecological functions including carbon sequestration. However, detailed quantification of tree biomass is usually limited to forest areas. Taking advantage of structural information available from stereo aerial imagery and airborne laser scanning (ALS), this research models tree biomass using national forest inventory data and linear least-square regression and applies the model both inside and outside of forest to create a nationwide model for tree biomass (above ground and below ground). Validation of the tree biomass model against TOF data within settlement areas shows relatively low model performance (R ² of 0.44) but still a considerable improvement on current biomass estimates used for greenhouse gas inventory and carbon accounting. We demonstrate an efficient and easily implementable approach to modelling tree biomass across a large heterogeneous nationwide area. The model offers significant opportunity for improved estimates on land use combination categories (CC) where tree biomass has either not been included or only roughly estimated until now. The ALS biomass model also offers the advantage of providing greater spatial resolution and greater within CC spatial variability compared to the current nationwide estimates.

IMp: The customizable LEGO(®) Pinned Insect Manipulator

We present a pinned insect manipulator (IMp) constructed of LEGO® building bricks with two axes of movement and two axes of rotation. In addition we present three variants of the IMp to emphasise the modular design, which facilitates resizing to meet the full range of pinned insect specimens, is fully customizable, collapsible, affordable and does not require specialist tools or knowledge to assemble.

Preparing for your annual staff appraisal: part 2

Annual appraisals are part of performance management and are designed to motivate, develop and support employees in performing their roles to the highest possible standard. They provide an opportunity for constructive discussion of performance, identification of areas for development and agreement of approaches by which employees needs could be met. Part 1 of this article was concerned with preparation of the employee and manager for annual staff appraisal. This article provides advice for managers who perform annual appraisal interviews. Guidance is offered on how to ensure the strategic objectives of the team and healthcare organisation are met, a balanced understanding of nurse performance is achieved, and future objectives are identified and agreed

Nonoccupational post-exposure prophylaxis source tracing: is it really feasible in Australia?

OBJECTIVE

A Swiss nonoccupational post-exposure prophylaxis (NPEP) source-tracing study successfully reduced unnecessary NPEP prescriptions by recruiting and testing source partners of unknown HIV serostatus. The Victorian NPEP Service in Australia attempted to replicate this study with the addition of HIV rapid testing and a mobile service.

METHODS

Patients presenting to two busy NPEP sites who reported a source partner of unknown HIV status were routinely asked if their source could be traced. If the exposed person indicated that their source partner was traceable they were asked to contact them and discuss the possibility of having an HIV test.

RESULTS

No sources were enrolled and the study was terminated.

CONCLUSION

We hypothesize that there are a number of differences between Australia and Switzerland that make source tracing unfeasible in Australia.

Improving clinical reasoning in children's nursing through narrative analysis

This article introduces the reader to the use of narratives to inform and enhance patient care. In this context narratives are specific stories about patient care that children's nurses discuss with one another, or with members of the multidisciplinary team, or that are relayed to them by patients and families. It is argued that an understanding of different narratives--children's, parents', young people's, our own and those of other healthcare professionals--will assist the children's nurse to act more sensitively, effectively and imaginatively.

Anthropogenic metal contamination and sapropel imprints in deep Mediterranean sediments

Sediment cores from the deep Balearic basin and the Cretan Sea provide evidence for the accumulation of Cd, Pd and Zn in the top few centimeters of the abyssal Mediterranean sea-bottom. In both cores, 206Pb/207Pb profiles confirm this anthropogenic impact with less radiogenic imprints toward surface sediments. The similarity between excess 210Pb accumulated in the top core and the 210Pb flux suggests that top core metal inventories reasonably reflect long-term atmospheric deposition to the open Mediterranean. Pb inventory in the western core for the past 100 years represents 20-30% of sediment coastal inventories, suggesting that long-term atmospheric deposition determined from coastal areas has to be used cautiously for mass balance calculations in the open Mediterranean. In the deeper section of both cores, Al normalized trace metal profiles suggest diagenetic remobilization of Fe, Mn, Cu and, to a lesser extent, Pb that likely corresponds to sapropel event S1.

Improving local healthcare policies and practices

Nurses often have an important role in devising or updating local policies and protocols, but are rarely prepared for a process that requires careful consideration of existing resources and the factors influencing change. This article explores and offers practical guidance on the process involved in preparing policies and protocols.

Medical, social and societal issues in infants with abusive head trauma

Abusive head trauma (AHT) is the leading cause of death from traumatic brain injury in under 2 year olds. AHT presents with acute encephalopathy, subdural hemorrhages and retinal hemorrhages occurring in the context of an inappropriate or inconsistent history. We retrospectively analyzed, over a 10 year period, admissions and transfers to our hospital with suspected AHT to assess patterns of presentation, presenting symptoms, investigations, subsequent confirmation, social work input and both neurological and social outcomes. We analyzed all suspected AHT infants and children looking for the time of presentation, presenting symptoms, caregivers concerns prior to presentation, a family profile including stressors, investigations (in particular neuroradiology and ophthalmology assessments), treatment in hospital, length of stay in hospital, social work involvement, subsequent discharge, neurological outcome and subsequent social work follow up. Data was collected from the hospital HIPE system, RIS (radiology reports system) and records from the social work department from a period October 1998 to January 2009 inclusive. Of 22 patients with confirmed AHT, ages seizures and irritability followed by vomiting, poor feeding, a bulging fontanelle and lethargy. The father was the sole minder in 5 cases. There was a delayed history in 4 cases. One had multiple visits to his GP. All cases had subdural hemorrhages proven by either CT or MRI scans and retinal hemorrhages diagnosed by ophthalmology. One infant presented with a torn frenulum. Four had suspicious bruising. All had normal coagulation profiles, skeletal surveys and extensive metabolic tests. Hospital stays ranged from 1 to 124 days (the median was 28 days and mean 33 days). Ten (45%) infants required ventilatory support. Sixteen infants had social work involvement within 4 days of admission (7 of these were interviewed immediately). Outcomes after case conferences were that 6 returned home with parents, 9 were placed in foster care. Four parents (18%) admitted to shakng their infants. There was 1 death. Thirteen (60%) were normal on follow up. Two had ADHD. Two had language delay. Two had motor delay. One criminal prosecution has ensued as yet Children with suspected AHT should undergo appropriate investigations which should include brain imaging, ophthalmic examination, skeletal survey and blood investigations. Early social work assessment is a priority as part of the multidisciplinary approach. A prospective national study of AHT is required.

Disseminating best practice through workshops

This article, the fourth in a five-part series, explores the ways in which best practice might be successfully disseminated through workshops. A workshop provides an exciting opportunity to engage nurses in new ways of thinking and the exploration of ideas applied to practice. It involves the nurse innovator in managing a learning experience that enables colleagues to explore their current and possible future practice. The article describes the different types of workshops available, the role of the workshop leader and the sorts of activities that might be used to encourage participation and practice development.

Disseminating best practice through teaching

A nurse may be invited to deliver teaching sessions to students at a local university, especially if he or she has a reputation as a practice innovator. These invitations are an opportunity for the nurse to disseminate practice wisdom to a wider audience. Planning the session so that it is educational, stimulating and represents the nurse's experience and expertise is crucial. While leading such a session may seem daunting, there are several strategies that can increase the chance of success, and these are discussed in this article.

Exploring attitudes towards older people's sexuality

Sexuality is an important part of life, for older people as well as for others. Sexual attitudes, beliefs and lifestyles may be as diverse among older people as they are among younger age groups. But for nurses to plan care with patients in ways that take issues of sexuality into account, they need to feel more comfortable talking about sexuality with older people. This article uses case studies to help readers explore their own attitudes and those of colleagues towards sexuality in later years, and prompts discussions on what this might signify for future nursing care so that staff are better equipped to assist patients with this subject.

Becoming a governor of an NHS foundation trust

Nurses have a key role in the successful governance of NHS foundation trusts, either as staff governors or representatives of the public. This article explores the role of the governor in each of these contexts and indicates some of the opportunities and challenges of representing stakeholder interests.

Body image in adolescents: insights and implications

This article explores some of the key processes associated with the development of a normal body image in adolescence and considers the impact of illness on the same. Nurses are assisted to explore the ways in which their insights into body image change might assist adolescents to cope with illness, injury or disability in a more constructive way.

Enhancing skills to develop practice

Nurses are skilful healthcare professionals, but the ability to develop skills depends on our readiness to evaluate what we do. This article describes a three-stage process, which helps nurses to analyse a particular skill and to decide what to do next.

Randomized clinical trial of the effect of adding subfascial endoscopic perforator surgery to standard great saphenous vein stripping

BACKGROUND

This randomized trial was undertaken to investigate the fate of incompetent perforating veins (IPVs) following saphenofemoral ligation and stripping of the great saphenous vein (GSV), with or without subfascial endoscopic perforator surgery (SEPS).

METHODS

Patients with venous reflux (greater than 0.5 s) of the GSV and additional IPVs were allocated randomly to standard surgery (saphenofemoral ligation, stripping and phlebectomies alone) or with the addition of SEPS. Patients with ulceration, recurrent veins, deep venous reflux/thrombosis or saphenopopliteal reflux were excluded. Duplex ultrasonography was carried out before operation, and at 1 week, 6 weeks, 6 months and 1 year after surgery. Quality of life questionnaires were completed and visual analogue scale scores collected at the same time points.

RESULTS

Thirty-eight patients were allocated to SEPS and 34 to the no SEPS group. Two patients in the no SEPS group were excluded (one withdrew and the other had the wrong treatment). There were no differences between the two groups with respect to pain, mobility or quality of life scores during follow-up. A significantly higher proportion of patients in the no SEPS group had IPVs on duplex imaging at 1 year (25 of 32 versus 12 of 38; P < 0.001).

CONCLUSION

IPVs do not remain closed following standard varicose vein surgery. The addition of SEPS was not associated with significant morbidity but did reduce the number of IPVs. Up to 1 year this had no effect on recurrence rates or quality of life, but late results remain to be seen.

REGISTRATION NUMBER

ISRCTN18288048 (http://www.controlled-trials.com).

Practice-based assessment: strategies for mentors

The reader is encouraged to investigate what is involved in the practice-based assessment of students and to consider how it might be improved. The author suggests that students should be assessed on their performance during episodes of care rather than by continuous assessment.

Location of glucose oxidase during production by Aspergillus niger

The production of the enzyme glucose oxidase by Aspergillus niger is well documented. However, its distribution within the fungal culture is less well defined. Since the enzyme location impacts significantly on enzyme recovery, this study quantifies the enzyme distribution between the extracellular fluid, cell wall, cytoplasm and slime mucilage fractions in an A. niger NRRL-3. The culture was separated into the individual fractions and the glucose oxidase activity was determined in each. The extracellular fluid contained 38% of the total activity. The remaining 62% was associated with the mycelia and was distributed between the cell wall, cytoplasm and slime mucilage in the proportions of 34, 12 and 16%, respectively. Intracellular cytoplasmic and cell wall sites were confirmed using immunocytochemical labelling of the mycelia. In the non-viable cell, the mycelial-associated enzyme was distributed between these sites, whereas in the viable cell, it was predominantly associated with the cell wall. The distribution of the enzyme activity indicates that recovery from the solids would result in a 38% loss, whereas recovery from the extracellular fluid would result in a 62% loss. The results also suggest, however, that this 62% loss could be reduced to around 34% by disintegrating the solids prior to separation due to the contribution of the enzyme in the cytoplasm and slime mucilage. This was confirmed by independently establishing the percentage activity in the liquid and solid portions of a disintegrated culture as 62 and 38%, respectively.

Accelerating Reinforcement Learning through Implicit Imitation

Imitation can be viewed as a means of enhancing learning in multiagent environments. It augments an agent's ability to learn useful behaviors by making intelligent use of the knowledge implicit in behaviors demonstrated by cooperative teachers or other more experienced agents. We propose and study a formal model of implicit imitation that can accelerate reinforcement learning dramatically in certain cases. Roughly, by observing a mentor, a reinforcement-learning agent can extract information about its own capabilities in, and the relative value of, unvisited parts of the state space. We study two specific instantiations of this model, one in which the learning agent and the mentor have identical abilities, and one designed to deal with agents and mentors with different action sets. We illustrate the benefits of implicit imitation by integrating it with prioritized sweeping, and demonstrating improved performance and convergence through observation of single and multiple mentors. Though we make some stringent assumptions regarding observability and possible interactions, we briefly comment on extensions of the model that relax these restricitions.

Overnight central and peripheral temperature changes in normal infants

AIM

To explore the relationship between central and peripheral temperature in normal infants after being put down to sleep.

METHODS

Overnight shin and rectal temperatures of 21 normal infants were continuously recorded at home for three nights at 2 wk, 6 wk, 3 mo and 5 mo of age. Parents documented the start and end of feed/nappy changes during the night.

RESULTS

An initial fall in rectal temperature was recorded on 149 out of 161 nights. This was linearly correlated with a rise in shin temperature for 106/149 (71%) nights (median R2 = 0.95, lower quartile 0.92, upper quartile 0.97). It was not possible to rule out a change in thermal insulation over the shins as a confounding variable in this strong association. However, a similar inverse relationship was seen between shin and rectal temperature during 111 of 121 (92%) feed/nappy changes.

CONCLUSION

The fall in rectal temperature after being put down to sleep may be due to redistribution of heat rather than decreased production or heat loss. If causal, the development in early infancy of an inverse relationship between shin and rectal temperature may be important for cardiovascular homeostasis. Further sleep laboratory work is required to distinguish peripheral temperature changes on falling asleep from those associated with changes in thermal insulation.

Central and peripheral temperature change in normal infants

The purpose was to explore the relationship between the fall in rectal temperature seen in normal infants after being put down to sleep and the concomitant rise in peripheral shin temperature. In this observational study 21 normal infants had continuous overnight peripheral shin and central rectal temperature recorded, for three nights at 2 weeks, 6 weeks, 3 months and 5 months of age. Parents documented the start and end of feed/nappy changing episodes during the night. All recordings were made in the infants' own home. A strong inverse linear correlation (median r2 = 0.95, lower quartile 0.92, upper quartile 0.97) was seen between rectal temperature and shin temperature on falling to sleep when put down on 106 (65%) of 161 nights. On many other nights a significant nonlinear association was present. It was not possible to exclude the process of being put down to sleep as a confounding variable in this strong association. However, a similar inverse relationship between shin and rectal temperature was seen overnight during 111 of 121 (92%) feed/nappy changing episodes. If causal, the development in early infancy of an inverse relationship between shin and rectal temperature may be important for cardiovascular homeostasis. Further sleep laboratory work including video recording is required to separate the peripheral and central temperature changes that take place on falling to sleep from those associated with removal of clothing during a nappy change.

Enquiry-based learning: an introductory guide

Enquiry-based learning uses real life situations to analyse and possibly refine nursing practice. Bob Price discusses the process.

Outpatient management of pelvic inflammatory disease

Pelvic inflammatory disease (PID) is a spectrum of inflammatory disorders of the female genital tract involving at least the endrometrium and may include the fallopian tubes, ovaries, and pelvic cavity. Over 1 million women each year are treated for PID in the United States, and it is one of the most serious infections diagnosed in women due to its sequelae. Women with PID acutely experience pain and are at risk for sepsis; however, the significant increases in ectopic pregnancy and infertility are the most disturbing long-term complications. It most often is initiated with an infection by a sexually transmitted disease, but can also involve a variety of pathogenic aerobes and anaerobes secondarily.

High-frequency oscillatory ventilation of the perfluorocarbon-filled lung: Dose-response relationships in an animal model of acute lung injury

OBJECTIVE

To examine dose-response relationships regarding the efficiency of gas exchange and hemodynamic function during high-frequency oscillation and partial liquid ventilation (HFO-PLV) of the perfluorocarbon (PFC)-treated lung in a model of acute lung injury.

SETTING

An animal research laboratory in a university medical center.

DESIGN

A prospective, randomized study comparing animals receiving varying doses (0, 5, 15, and 20 mL/kg) of perflubron during high-frequency oscillatory ventilation (HFOV) with mean airway pressure (Paw) optimized to achieve a minimal percutaneous oxygen saturation (Spo2).

SUBJECTS

Nineteen healthy swine (mean weight 28.9 kg) with saline lavage-induced acute lung injury.

METHODS

Animals were treated with repetitive saline lavage to achieve a uniform degree of acute lung injury (Spo2 < or =90% on an Fio2 of 1.0). After lung injury, subjects were converted to HFOV, and lung volume was optimized. HFO-PLV was initiated by instillation of perflubron at a rate of 0.5 mL.kg-1.min-1 to achieve total doses of 5, 15, and 20 mL/kg. After PFC dosing, the only experimental manipulation consisted of adjustment of Paw to achieve an Spo2 of 90% +/- 2% with Fio2 of 0.6. Gas exchange, hemodynamic variables, and pulmonary mechanics data were collected over a 1-hr period. Five control animals were not dosed with perflubron and remained on HFOV for the 1-hr period of data collection.

MEASUREMENTS AND MAIN RESULTS

After lung volume recruitment with HFOV, the initiation of HFO-PLV was best tolerated with the two lower doses in our protocol. There were essentially no changes in Paco2 or pH between groups over the dosing interval. After dosing, analysis of variance demonstrated a PFC dose-dependent effect for oxygenation index (p =.01) only; the lowest oxygenation index was found in the 15 mL/kg group (p =.01). In the 15 mL/kg group, the Paw decreased steadily from 20.6 +/- 3.4 cm H2O at the end of dosing to 18.0 +/- 4.9 cm H2O at 60 mins. The Pao2 increased from 113 +/- 51 torr (15.06 +/- 6.79 kPa) to 134 +/- 49 torr (17.86 +/- 6.53 kPa) during this period and was associated with a decreasing oxygenation index (from 11.4 +/- 2.0 to 9.3 +/- 1.5). The cardiac index and pulmonary vascular resistance did not change significantly during the dosing period and were relatively stable after the completion of dosing.

CONCLUSIONS

The combination of HFOV and perflubron administration was well tolerated hemodynamically and was not associated with deterioration of gas exchange during dosing. Our data suggest that the optimal dose of perflubron to achieve the lowest oxygenation index during HFO-PLV is between 5 and 15 mL/kg. The combination of HFOV and perflubron administration is a novel strategy in the treatment of acute lung injury that shows some promise and merits additional investigation. We hope in future studies to address the histopathologic effects of varying perflubron doses during HFOV in a long-term study of the lung-protective effects of HFO-PLV.

Optimizing intrapulmonary perfluorocarbon distribution: Fluoroscopic comparison of mode of ventilation and body position

OBJECTIVE

Partial liquid ventilation with the perfluorochemical, perflubron, has been shown to improve lung mechanics and enhance gas exchange in the treatment of severe acute lung injury. However, the most effective strategy to provide optimal intrapulmonary distribution of perflubron has not been fully accessed. The objective of this study was to examine the effect of body position (supine vs. rotational) and mode of ventilation (conventional mechanical ventilation [CMV] vs. high-frequency oscillatory ventilation [HFOV]) on perflubron distribution and oxygenation improvement.

DESIGN

Prospective, randomized, animal trial.

SETTING

Research laboratory at a university medical center.

SUBJECTS

Twenty healthy piglets (4.5-6.6 kg).

INTERVENTIONS

Subjects underwent repetitive saline lavage to achieve a uniform degree of lung injury and then were randomized to either CMV or were converted to HFOV. Within each ventilator group, animals were randomized to supine positioning (S) or rotational positioning with alternation between supine and prone position (R) during incremental dosing of three 5-mL/kg doses of perflubron.

MEASUREMENTS AND MAIN RESULTS

Arterial blood gas tensions, hemodynamic variables, and the oxygenation index were recorded after each dose of 5 mL/kg. Lateral cinefluoroscopic images after each dose were digitized for computer analysis of density. A density index was calculated for a 2-cm2 window in three dorsal and three ventral lung regions. Uniformity of distribution was calculated by comparing the mean density among the six regions. Oxygenation improvements were compared between groups. There were no significant differences in hemodynamic variables or gas exchange after lung injury in the four groups. Rotational positioning produced significantly more uniform perflubron distribution during both CMV and HFOV. This effect was independent of the mode of ventilation. The mean ventral density index was affected by rotating position and HFOV mode of ventilation after 10 mL/kg of perflubron, and rotating position was affected only after 15 mL/kg of perflubron. There was a significant reduction in the oxygenation index from baseline to end lavage in both CMV groups, as well as all of the animals that were rotated.

CONCLUSION

Perflubron is more uniformly dispersed when dosed in a rotational fashion with alternation between supine and prone position during incremental dosing. This effect is independent of mode of ventilation. There was no relationship between oxygenation improvements and nondependent perflubron distribution. CMV and rotating dosing both led to a significant decrease in the oxygenation index after a 15 mL/kg dose of perflubron. This information has important impact on the future development of dosing strategies and clinical trial design.

M100,907, a selective 5-HT(2A) antagonist, attenuates dopamine release in the rat medial prefrontal cortex

Previous research has suggested that serotonin 5-HT(2A) receptors modulate the functioning of the mesocortical dopamine (DA) pathway. However, the specific role of 5-HT(2A) receptors localized within the medial prefrontal cortex (mPFC) is not known. The present study employed in vivo microdialysis to examine the role of this receptor in the modulation of basal and K(+)-stimulated (Ca(2+)-dependent) DA release. The selective 5-HT(2A) antagonist M100,907 was infused directly into the mPFC of conscious rats. This resulted in a concentration-dependent blockade of K(+)-stimulated DA release. Intracortical application of M100,907 also blocked increases in DA release produced by the systemic administration of the 5-HT(2A/2C) agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). These findings demonstrate that local 5-HT(2A) antagonism has an inhibitory effect on stimulated, Ca(2+)-dependent DA release. They suggest that cortical 5-HT(2A) receptors potentiate the phasic release of mesocortical DA.

Problem-based learning in clinical practice facilitating critical thinking

Problem-based learning has established a strong reputation within education programs delivered to a wide variety of healthcare professionals. Nevertheless, most accounts of problem-based learning relate to classroom settings, where issues of patient safety and competing demands upon time are not a primary concern. The authors explore ways in which problem-based learning may be utilized within clinical practice to enhance the professional development of nurses. A framework for thinking about problems and professional responses is outlined, and illustrations are drawn from the maternal-child health practice setting.

Neutrophil tissue inhibitor of matrix metalloproteinases-1 occurs in novel vesicles that do not fuse with the phagosome

The human neutrophil granule location of precursors of matrix metalloproteinases (MMPs), MMP-8 and -9, has been established, but that of the tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) has not. In this study, labeling for TIMP-1, pro-MMP-8, pro-MMP-9, and established granule marker proteins reveals that TIMP-1 is mainly located in distinct oval, electron translucent organelles, a little larger than azurophil granules. A lack of labeling for the fluid phase endocytic marker, bovine serum albumin-gold, the lysosome-associated membrane protein markers, and for glycosylphosphatidylinositol-linked proteins, which are enriched in secretory vesicles, indicates the non-endosomal, non-lysosomal, and non-secretory nature of this organelle. Density gradient cofractionation with the least dense, secretory population and some pleomorphism of the organelle suggest it is a "vesicle" rather than a "granule" population. Colocalization with pro-MMP-9 or pro-MMP-8, in minor subpopulations, suggests that TIMP-1 vesicle biogenesis occurs between metamyelocytic and terminal differentiation and before secretory vesicle synthesis. Pulse-chased IgG-coated latex beads and immunolabeling show that specific and azurophil granules fuse with the phagosome whereas TIMP-1 and pro-MMP-9-containing organelles do not. This suggests that these play no role in phagosomal destruction of IgG-opsonized bacteria. Separate localization and colocalization of these proteins may, however, facilitate fine regulation of extracellular proteolysis.

Altered body image: managing social encounters

For terminally ill people who are still active within the community, altered body image can pose significant problems. Patients may have an obvious change in appearance or function, but be unsure how to present a positive image to others. Moreover, lay supporters are often equally unsure how to react to the changed appearance of the dying person. Changes in physical appearance and function associated with disease processes (and sometimes treatment) need to be integrated into the interaction that occurs between patients and lay carers. This is likely to be a difficult matter to facilitate, taxing the ingenuity of the palliative care nurse who hopes to assist the patient in this regard. This article uses a case study from the community-based palliative care setting to introduce steps that nurses and patients might consider as the patient sets out to manage such social encounters.

Problem-based learning the distance learning way: a bridge too far?

Since problem-based learning is classically associated with campus based, small group learning conducted over protracted periods of time, it should not, in theory, be well suited to the distance learning mode of study. Just how do you write distance learning materials which adequately accommodate the problem-based learning process, and which acknowledge the variety of problems that could be identified for study? This paper critically examines one distance learning initiative designed to test whether problem-based learning may be delivered to student benefit at post-registration, undergraduate nurse programme level.

A Streptomyces coelicolor antibiotic regulatory gene, absB, encodes an RNase III homolog

Streptomyces coelicolor produces four genetically and structurally distinct antibiotics in a growth-phase-dependent manner. S. coelicolor mutants globally deficient in antibiotic production (Abs(-) phenotype) have previously been isolated, and some of these were found to define the absB locus. In this study, we isolated absB-complementing DNA and show that it encodes the S. coelicolor homolog of RNase III (rnc). Several lines of evidence indicate that the absB mutant global defect in antibiotic synthesis is due to a deficiency in RNase III. In marker exchange experiments, the S. coelicolor rnc gene rescued absB mutants, restoring antibiotic production. Sequencing the DNA of absB mutants confirmed that the absB mutations lay in the rnc open reading frame. Constructed disruptions of rnc in both S. coelicolor 1501 and Streptomyces lividans 1326 caused an Abs(-) phenotype. An absB mutation caused accumulation of 30S rRNA precursors, as had previously been reported for E. coli rnc mutants. The absB gene is widely conserved in streptomycetes. We speculate on why an RNase III deficiency could globally affect the synthesis of antibiotics.

Induction of the mesendoderm in the zebrafish germ ring by yolk cell-derived TGF-beta family signals and discrimination of mesoderm and endoderm by FGF

The endoderm forms the gut and associated organs, and develops from a layer of cells which emerges during gastrula stages in the vertebrate embryo. In comparison to mesoderm and ectoderm, little is known about the signals which induce the endoderm. The origin of the endoderm is intimately linked with that of mesoderm, both by their position in the embryo, and by the molecules that can induce them. We characterised a gene, zebrafish gata5, which is expressed in the endoderm from blastula stages and show that its transcription is induced by signals originating from the yolk cell. These signals also induce the mesoderm-expressed transcription factor no tail (ntl), whose initial expression coincides with gata5 in the cells closest to the blastoderm margin, then spreads to encompass the germ ring. We have characterised the induction of these genes and show that ectopic expression of activin induces gata5 and ntl in a pattern which mimics the endogenous expression, while expression of a dominant negative activin receptor abolishes ntl and gata5 expression. Injection of RNA encoding a constitutively active activin receptor leads to ectopic expression of gata5 and ntl. gata5 is activated cell-autonomously, whereas ntl is induced in cells distant from those which have received the RNA, showing that although expression of both genes is induced by a TGF-beta signal, expression of ntl then spreads by a relay mechanism. Expression of a fibroblast growth factor (eFGF) or a dominant negatively acting FGF receptor shows that ntl but not gata5 is regulated by FGF signalling, implying that this may be the relay signal leading to the spread of ntl expression. In embryos lacking both squint and cyclops, members of the nodal group of TGF-beta related molecules, gata5 expression in the blastoderm is abolished, making these factors primary candidates for the endogenous TGF-beta signal inducing gata5.