Testing novel strategies for patients hospitalised with HIV-associated disseminated tuberculosis (NewStrat-TB): protocol for a randomised controlled trial

BACKGROUND

HIV-associated tuberculosis (TB) contributes disproportionately to global tuberculosis mortality. Patients hospitalised at the time of the diagnosis of HIV-associated disseminated TB are typically severely ill and have a high mortality risk despite initiation of tuberculosis treatment. The objective of the study is to assess the safety and efficacy of both intensified TB treatment (high dose rifampicin plus levofloxacin) and immunomodulation with corticosteroids as interventions to reduce early mortality in hospitalised patients with HIV-associated disseminated TB.

METHODS

This is a phase III randomised controlled superiority trial, evaluating two interventions in a 2 × 2 factorial design: (1) high dose rifampicin (35 mg/kg/day) plus levofloxacin added to standard TB treatment for the first 14 days versus standard tuberculosis treatment and (2) adjunctive corticosteroids (prednisone 1.5 mg/kg/day) versus identical placebo for the first 14 days of TB treatment. The study population is HIV-positive patients diagnosed with disseminated TB (defined as being positive by at least one of the following assays: urine Alere LAM, urine Xpert MTB/RIF Ultra or blood Xpert MTB/RIF Ultra) during a hospital admission. The primary endpoint is all-cause mortality at 12 weeks comparing, first, patients receiving intensified TB treatment to standard of care and, second, patients receiving corticosteroids to those receiving placebo. Analysis of the primary endpoint will be by intention to treat. Secondary endpoints include all-cause mortality at 2 and 24 weeks. Safety and tolerability endpoints include hepatoxicity evaluations and corticosteroid-related adverse events.

DISCUSSION

Disseminated TB is characterised by a high mycobacterial load and patients are often critically ill at presentation, with features of sepsis, which carries a high mortality risk. Interventions that reduce this high mycobacterial load or modulate associated immune activation could potentially reduce mortality. If found to be safe and effective, the interventions being evaluated in this trial could be easily implemented in clinical practice.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04951986. Registered on 7 July 2021 https://clinicaltrials.gov/study/NCT04951986.

The Evolving Spectrum of Kidney Histology in HIV-Positive Patients in South Africa

Introduction

Sub-Saharan Africa remains challenged by the highest burden of human immunodeficiency virus (HIV), an epidemic of tuberculosis (TB), and increasing number of people with HIV (PWH) on antiretroviral therapy (ART), all of which may result in kidney injury.

Methods

This observational cohort study describes the spectrum of kidney disease in PWH in South Africa, between 2005 and 2020. Kidney biopsies were analyzed in 4 time periods as follows: early ART rollout (2005-2009), tenofovir disoproxil (TDF) introduction (2010-2012), TDF-based fixed dose combination (2013-2015), and ART at HIV diagnosis (2016-2020). Logistic regression was used to identify factors associated with HIV-associated nephropathy or focal segmental glomerulosclerosis (HIVAN/FSGS) and tubulointerstitial disease (TID).

Results

We included 671 participants (median age 36, interquartile range, 21-44 years; 49% female; median CD4 cell count 162 [interquartile range, 63-345] cells/mm3). Over time, ART (31%-65%, P < 0.001), rate of HIV suppression (20%-43%, P < 0.001), nonelective biopsies (53%-72%, P < 0.001), and creatinine at biopsy (242-449 μmol/l, P < 0.001) increased. A decrease in HIVAN (45%-29% P < 0.001) was accompanied by an increase in TID (13%-33%, P < 0.001). Granulomatous interstitial nephritis accounted for 48% of TID, mostly because of TB. Exposure to TDF was strongly associated with TID (adjusted odds ratio 2.99, 95% confidence interval 1.89-4.73 P < 0.001).

Conclusion

As ART programs intensified and increasingly used TDF, the spectrum of kidney histology in PWH evolved from a predominance of HIVAN in the early ART era to TID in recent times. The increase in TID is likely due to multiple exposures that include TB, sepsis, and TDF as well as other insults.

Trends in Diagnosis of Noninvasive Follicular Thyroid Neoplasm With Papillarylike Nuclear Features and Total Thyroidectomies for Patients With Papillary Thyroid Neoplasms

Importance

Increasing detection of early-stage papillary thyroid neoplasms without improvements in mortality has prompted development of strategies to prevent or mitigate overtreatment.

Objective

To determine adoption rates of 2 recent strategies developed to limit overtreatment of low-risk thyroid cancers: (1) a new classification, noninvasive follicular thyroid neoplasm with papillarylike nuclear features (NIFTP), and (2) hemithyroidectomy for selected papillary thyroid carcinomas (PTCs) up to 4 cm in size.

Design, Setting, and Participants

This is a cross-sectional analysis of 3368 pathology records of 2 cohorts of patients from 18 hospitals in 6 countries during 2 time periods (2015 and 2019). Participating hospitals were included from the US (n = 12), Canada (n = 2), Denmark (n = 1), South Korea (n = 1), South Africa (n = 1), and India (n = 1). The records of the first 100 patients per institution for each year who underwent thyroid-directed surgery (hemithyroidectomy, total thyroidectomy, or completion thyroidectomy) were reviewed.

Main Outcomes and Measures

Frequency of diagnosis of NIFTP, PTCs, and thyroidectomies during the study period.

Results

Of the 790 papillary thyroid neoplasms captured in the 2019 cohort, 38 (4.8%) were diagnosed as NIFTP. Diagnosis of NIFTP was observed in the US, South Africa, and India. There was minimal difference in the total proportion of PTCs in the 2015 cohort compared with the 2019 cohort (778 [47.1%] vs 752 [44.5%]; difference, 2.6% [95% CI, -16.9% to 22.1%]). The proportion of PTCs eligible for hemithyroidectomy but treated with total thyroidectomy in the 2 cohorts demonstrated a decreasing trend from 2015 to 2019 (341 of 453 [75.3%] vs 253 of 434 [58.3%]; difference, 17.0% [95% CI, -1.2% to 35.2%]).

Conclusions and Relevance

Results of this cohort study showed that the 2 mitigation strategies for preventing overtreatment of early-stage thyroid cancer have had mixed success. The diagnosis of NIFTP has only been applied to a small proportion of thyroid neoplasms compared with expected rates. However, more patients eligible for hemithyroidectomy received it in 2019 compared with 2015, showing some success with this deescalation strategy.

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.

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.

A simple and rapid scanning electron microscope preparative technique for delicate "gymnodinioid" dinoflagellates

Light microscopy (LM) is routinely used to investigate delicate (unarmoured and lightly armoured) "gymnodinioid" dinoflagellate species but at this level of resolution, morphological features such as apical grooves, apical pores, thin thecal plates, and scales are often difficult to observe, thereby necessitating the use of scanning electron microscopy (SEM). Good results were obtained when harvested cells were fixed with osmium tetroxide (OsO(4)) as the primary fixative, adhered with poly-L-lysine to round glass coverslips, dehydrated in an ethanol series, and dried with hexamethyldisilazane (HMDS). Poly-L-lysine has in the past effectively been used to adhere biological material such as human red blood cells, mouse leukemic cells, and marine dinoflagellates to glass coverslips. HMDS has been used to substitute critical point drying (CPD) to dry soft insect tissues, rat hepatic endothelial cells, and the cilia of rat trachea. By combining and fine-tuning these two protocols in SEM studies of delicate "gymnodinioid" dinoflagellates, it is possible to overcome cell distortion such as shrinking and collapsing that result from centrifuging, filtering, and CPD. The combination of poly-L-lysine and HMDS not only produces good results but also requires limited expertise and equipment, is inexpensive, and is less time-consuming.

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.

Novel non-isotopic detection of MutY enzyme-recognized mismatches in DNA via ultrasensitive detection of aldehydes

A highly sensitive method to detect traces of aldehyde-containing apurinic/apyrimidinic (AP) sites in nucleic acids has been developed. Based on this method, a novel approach to detect DNA base mismatches recognized by the mismatch repair glycosylase MutY is demonstrated. Open chain aldehydes generated in nucleic acids due to spontaneous depurination, DNA damage or base excision of mismatched adenine by MutY are covalently trapped by a new linker molecule [fluorescent aldehyde-reactive probe (FARP), a fluorescein-conjugated hydroxylamine derivative]. DNA containing AP sites is FARP-trapped, biotinylated and immobilized onto neutravidin-coated microplates. The number of FARP-trapped aldehydes is then determined via chemiluminescence using a cooled ICCD camera. AP sites induced in plasmid or genomic calf thymus DNA via mild depurination or by simple incubation at physiological conditions (pH 7, 37 degreesC) presented a linear increase in chemiluminescence signal with time. The procedure developed, from a starting DNA material of approximately 100 ng, allows detection of attomole level (10(-18) mol) AP sites, or 1 AP site/2 x 10(7) bases, and extends by 1-2 orders of magnitude the current limit in AP site detection. In order to detect MutY-recognized mismatches, nucleic acids are first treated with 5 mM hydroxylamine to remove traces of spontaneous aldehydes. Following MutY treatment and FARP-labeling, oligonucleotides engineered to have a centrally located A/G mismatch demonstrate a strong chemiluminescence signal. Similarly, single-stranded M13 DNA that forms mismatches via self-complementation (average of 3 mismatches over 7429 bases) and treated with MutY yields a signal approximately 100-fold above background. No signal was detected when DNA without mismatches was used. The current development allows sensitive, non-isotopic, high throughput screening of diverse nucleic acids for AP sites and mismatches in a microplate-based format.

Explorations in body image care: Peplau and practice knowledge

Practitioners in mental health care have long utilized the work of Hildegard Peplau, both for nursing discourse and for practice. At a time when the role of theory in practice is once more being debated, and when theories are being applied in new contexts, this paper examines the contribution that Peplau's work may have to offer altered body image nursing care. A case study is used to highlight concepts in practice, the paper examining the ways in which Peplau's Theory of Interpersonal Relations complement the other elements of practice knowledge that the nurse uses to assist patients and lay carers alike.

Making midwifery decisions

In order to share practice decision making with women, midwives need to understand their own tacit knowledge and some of the heuristic processes used to arrive at clinical decisions. Arguing that midwifery decision making is intuitive and artful is insufficient defence when accounting for professional practice. Explicit reasoning, individual and shared, should be well to the fore. Contrary to received wisdom, expert practitioners can share their midwifery reasoning with junior colleagues. Role modelling decision making process involves the senior midwife in understanding her own tacit knowledge and coming to terms with practice discussion as a pursuit of understanding, rather than a blame culture activity.